RWWD and Child Support Registrar (Child support second review) - [2025] ARTA 1926

RWWD and Child Support Registrar (Child support second review) [2025] ARTA 1926 (17 September 2025)
Applicant/s: RWWD
Respondent:  Child Support Registrar
Other party:  XNPS
Tribunal Number:                2024/4003

Tribunal:Senior Member M Kennedy
Place:Adelaide
Date:17 September 2025
Decision:The decision of the Administrative Appeals Tribunal of 31 May 2024 is set aside and substituted with a decision affirming the decision to disallow Mr XNPS’ objection.

……………..[sgnd]………………..
Senior Member M Kennedy
Names used in all published decisions are pseudonyms. Any references appearing in square brackets indicate that information has been removed from this decision and replaced with generic information so as not to identify involved individuals as required by subsections 201(1A) - 201(1B) of the Child Support (Registration and Collection) Act 1988
Catchwords
Child support – care percentage determination – revocation of existing care percentage determination – making of new care percentage determination – decision set aside and substituted with a decision affirming the decision to disallow objection
Legislation
Child Support Assessment Act 1989
Statement of Reasons

Ms RWWD and Mr XNPS are the parents of two children, in respect of whom a child support liability is in place. Under that liability, at all material times, Mr XNPS has had a liability to pay child support to Ms RWWD. These proceedings pertain to the care percentage determinations forming part of the calculation of the child support liability.
From 28 October 2021, the child support liability had been calculated on the basis that Mr XNPS had 42% care of the children and Ms RWWD had 58% care. The care percentage determination was said to be reflective of a verbal agreement between the parents.
On 4 May 2023, Ms RWWD notified Services Australia that care had changed from 25 January 2023. On 8 June 2023, Mr XNPS communicated to Services Australia that he did not agree that care arrangements had changed.
On 3 August 2023, Services Australia decided that care had changed, revoked the existing care percentage determinations and replaced them with determinations reflecting Ms RWWD having 67% care and Mr XNPS having 33% care from 1 February 2023. On 7 October 2023, Mr XNPS objected to that decision.
Contemporaneously, Services Australia also made a further care change determination the same day following a subsequent notification of a further change of care event on 10 July 2023. That decision is not before the Tribunal, but is mentioned only to demonstrate that the care determination decision that is before the Tribunal only has potential application for a limited duration. That decision put in place care percentage determinations reflecting 63% care to Ms RWWD and 37% care to Mr XNPS.
Mr XNPS’ objection to the decision of 3 August 2023 effectively putting in place care percentage determinations from 1 February 2023 of 67% to Ms RWWD and 33% to himself was dealt with in a decision dated 27 January 2024. The objection was disallowed.
Mr XNPS applied to the Administrative Appeals Tribunal (AAT) for review on 30 January 2024. The AAT set aside the decision under review and allowed Mr XNPS’ objection, essentially leaving in place the care percentage determination that had been in place since 28 October 2021.
The factual controversy that the AAT was called upon to address was somewhat limited, and the decision turned on the AAT’s perception that what changes had taken place were ‘one-off temporary events to accommodate incidental interruptions to the care pattern due to Mr XNPS’ business commitments’. The AAT decided that there had been no change to the pattern of care, and therefore the existing care percentage determinations should continue to apply.
Ms RWWD applied to the AAT for second review of the decision on 18 June 2024.
On 14 October 2024, the AAT was abolished and the Administrative Review Tribunal commenced operations. Under the transitional provisions in the Administrative Review Tribunal (Consequential and Transitional Provisions No. 1) Act 2024 (the Transitional Act), applications for review that were not finalised by the Administrative Appeals Tribunal before 14 October 2024 were taken to be applications for review to the Administrative Review Tribunal (hereafter the Tribunal). The Transitional Act gives the Tribunal the authority to continue and finalise any aspect of the review not already completed.
On 15 September 2025, Mr XNPS communicated with the Tribunal to the effect that he did not wish to participate in the hearing listed for the following day. He provided brief submissions essentially supporting the approach of the AAT.
The hearing proceeded on 16 September 2025 in Mr XNPS’ absence.
CONSIDERATION
Under the scheme for determining percentages of care for use in the administrative assessment of child support, existing care determinations continue in effect until such time as they are revoked. The circumstances in which an existing care determination may be revoked are restricted to those set out in Division 4, Subdivision C of the Act.
Relevantly to the circumstances of this case[1], section 54F of the Act provides for revocation of a determination of a percentage of care if (among other requirements):
·      the Registrar or Secretary is notified, or otherwise becomes aware, that the care of the child that is actually taking place does not correspond with the person’s existing percentage of care; and
·      the Registrar is satisfied that the person’s cost percentage for the child would change if the Registrar were to determine another percentage to be the person’s percentage of care for the child.
·      If a new percentage of care (under the applicable provisions) were to be determined, it would not be the same as the existing percentage of care.
[1] Revocation is also provided for by sections 54G and 54H of the Assessment Act. Without reproducing that legislation, as explained by the court in Child Support Registrar v BKZC [2023] 1109 at [101], it is necessary to consider first, the position under section 54G, and if section 54G does not apply, the position under section 54F, and only if section 54F does not apply the position under section 54H. Section 54G will apply where a parent has no care of a child despite the other [parent] making the child available.
The existing care percentage is revoked
Noting that the AAT had identified little in dispute between the parents as to the actual care arrangements between the parents at material times, I explored with Ms RWWD her purpose and objective in seeking second review of the AAT’s decision.
Ultimately, I understood Ms RWWD to raise three points:
·First, Ms RWWD initially indicated she did not take issue with the remarks made by the AAT to the effect that the series of one-off changes did not amount to a change to the pattern of care. Ms RWWD clarified that she did not agree with that assessment but understood why the AAT might view the matter that way.
·Second, Ms RWWD took issue with calculations mentioned by the AAT, and considered them to be incorrect. Ms RWWD was unable to put her finger on specifically which figures in the AAT’s decision were incorrect, but in the course of further evidence and submissions I understood Ms RWWD’s concerns in this regard to settle on the summation of her evidence made by the AAT member as follows:
[10] However, she acknowledged and agreed that from 9 July 2023, he [Mr XNPS] had resumed his pre-existing care pattern of five nights per fortnight in school term time and half the school holidays.
·Ms RWWD’s position as explained to me was that there was no arrangement where the children would spend half the school holidays with Mr XNPS that could be resumed at that time. Ms RWWD said that the arrangement regarding half the school holidays, and particularly half the long school holidays, was not made until July, and so therefore it was incorrect to attribute her to have said that such an arrangement ‘resumed’.
·Third, Ms RWWD said that contrary to the summation of Mr XNPS’s evidence at paragraph [15] of the AAT’s decision, from approximately 1 February 2023, Mr XNPS missed each and every one of his previous Sunday night care events, and it was not the case that only approximately six such nights were missed.
Other than submissions accompanying the application for second review, and Mr XNPS’s submissions provided the day before the hearing, and a small volume of historical supplementary documents, the documentary evidence before me is essentially the same as that which was before the AAT.
Reviewing that evidence, I note that records produced regarding the care percentage determination in place from 28 October 2021 were identified based on an arrangement where Mr XNPS had care of the children on Wednesday, Thursday and Saturday of one week, and Wednesday, Thursday and Sunday of the next week[2]. That arrangement correctly translates through to care percentage determinations of 58% : 42% , and as mentioned by Ms RWWD does not incorporate any separate arrangement for school holiday care.
[2] S1
Ms RWWD is attributed to have notified Services Australia on 4 May 2023 that Mr XNPS was only having 5 nights per fortnight care but he was also semi-regularly travelling for work.[3]
[3] T6 folio 26
It is of note that the first documented contact with Mr XNPS[4] conflates a response to Ms RWWD’s notification and possibly a new report of a care change. Mr XNPS is attributed to have said that the regular arrangements are Tuesday and Wednesday every week, alternate Saturday nights and 50% of the school holidays. The note attributes Mr XNPS to confirm that he no longer has Sunday night fortnightly the amounts to the notification of the next change of care. Mr XNPS said he had not missed any dates of care in the last six months.
[4] T10 folio 30
In a further accompanying document[5] Mr XNPS further explains “an alternative Sunday night has unfortunately recently been forfeited by myself due to ….”. Further correspondence between the parties addresses the impact of particular instances of travel on the care arrangements, and also ad hoc departures due to family arrangements.
[5] T11, folio 32
It is clear from subsequent records that the Services Australia officer considering the matter interpreted what Mr XNPS had said as confirmation of a change of 1 night each fortnight, notwithstanding Mr XNPS’ initial statement that he had not missed any dates of care in the last six months.[6]
[6] T14 folio 38
A further contact of 17 July 2023 attributes Mr XNPS to acknowledge that “some time in Feb 23 his care dropped to 5npf”, and it is reference to this note that the notion of 50% of school holidays is incorporated into the understanding of the pre-existing care arrangements. I note this is contrary to the evidence of Ms RWWD who said that prior to July 2023, the pattern of 6 nights per fortnight (and then 5 nights per fortnight on her case) continued through the school holiday period. Ms RWWD’s position in the Tribunal hearing on this point reflects what she is attributed to have said to Services Australia on 18 July 2023.[7] Her remarks in this regard are contemporaneous with her reporting the further change to the care arrangements incorporating 50% of school holiday care from 10 July 2023.[8]
[7] T19 folio 46
[8] T20, folio 47
On 26 July 2023, Mr XNPS provided a written submission[9] where he said that his care had never dropped below 5 nights per fortnight, before identifying instances of ad hoc variation.
[9] T29, folio 82
At this point it is convenient to recall that the existing care percentage determinations are based on Mr XNPS having six nights per fortnight, and in this submission which serves as a summary of what has transpired to that point, Mr XNPS is stating that his care has not dropped below 5 nights per fortnight. A statement by a redacted deponent whose first name is Thomas[10] corroborates Mr XNPS’s position that from February 2021 he has had a (minimum) of 5 nights per fortnight.
[10] T32, folio 100
I have also considered calendar evidence submitted by both parties. It is not self-evident that those documents, which are printed representations of digital calendar programmes, are always reflecting what actually happened or are instead reflecting what was understood to be likely to be going to happen when the calendar data was entered, or perhaps a combination of both. Ms RWWD attempted to provide further explanation of her records in this regard, but I am not confident to rely on those records, or those of Mr XNPS as conclusive.
Overall, I am satisfied to find that from 1 February 2021, Mr XNPS’s previous pattern of 6 nights per fortnight care had changed to 5 nights per fortnight care. It appears there were also further ad hoc instances of missed care events due to Mr XNPS’s work commitments.
Unlike the AAT member, I consider that the acknowledged reduction from 6 nights per fortnight to 5 nights per fortnight does present a material change to the pattern of care extending beyond ad hoc or occasional variations. It appears that there were also such ad hoc or occasional variations in this case, and I agree that such ad hoc occasional variations should not, of themselves, justify a finding that the care of the child that is actually taking place does not correspond with the person’s existing percentage of care. However, I consider that behind those ad hoc variations there is also a change to the underlying and substantive pattern, and my finding appears to accord with the representations Mr XNPS made to Services Australia at the time, as documented above.
A change from 6 nights per fortnight to 5 nights per fortnight is of substance. Across a care period of a fortnight it is the difference between 42% for Mr XNPS and 36% for Mr XNPS,[11] with the balance to Ms RWWP. Such a change to the care percentage determination produces changes to the cost percentage from 39% to 26% in accordance with section 55C of the Assessment Act. It therefore impacts on the calculation of the child support liability in a real way.
[11] 6/14 x 100% and 5/14 x 100%.
Returning to my statutory task in light of these findings, section 54F of the Assessment Act obliges me to revoke the existing care percentage determination because I am satisfied that the care of the children that was actually taking place does not correspond with the parent’s existing percentage of care, that the cost percentage would change if I were to determine another percentage, and that the new percentage of care will not be the same as the existing percentage of care.
I find the care change day to be 1 February 2023, albeit recognising there is some degree of imprecision in that regard in light of the evidence.
Subsection 54F(3) regulates from what date the existing care percentage will be revoked. If the Child Support Registrar had been informed within 28 days of the change of care day, then the revocation would take effect for both parents from the day before that day. If the Child Support Registrar were informed of the change more than 28 days after the change of care day, then the existing care percentage determination would be revoked from different days for each parent, with the parent with a reduction in care being impacted from the day care reduced, and the parent with increased care being benefited only from the day the Child Support Registrar was informed of the change.
I find that the care changed on 1 February 2023, and the Child Support Registrar was notified on 4 May 2023, outside the period of 28 days. The existing care percentage determination is revoked for Mr XNPS from the day before the care change day; namely 31 January 2023. The existing care percentage determination for Ms RWWD is revoked from the day before the day the Child Support Registrar was notified; namely, 3 May 2023.
Sections 49 and 50 of the Assessment Act then provides that if a care percentage determination is revoked under section 54F of the Assessment Act, it is necessary to determine the person's percentage of care for the child during the care period, and it must correspond with the actual care of the child the person has or is likely to have during the care period. That determination will take effect from the day after the previous care determination was revoked in respect of each parent: section 54B(2)(c)(ii) of the Act.
The new care percentage determinations
Applying my findings expressed above at paragraph 29 to the making of a new care percentage determination, which in this case takes place pursuant to section 50 of the Act, I identify a care period of 14 days, reflecting the fortnight over which I have found the pattern of care to manifest. Little turns on the duration of the care period in these circumstances beyond one fortnight given the purpose of the care period is essentially to convert the pattern of care into a percentage figure. With the extant care percentage determination revoked, I find the new care percentage determinations to be 37% in respect of Mr XNPS and 63% in respect of Ms RWWS. Each care percentage determination takes effect from the day after the revocation of the previous care determination in respect of each parent.
My decision on second review is the same decision as was reached by Services Australia at first instance and the objection to which was disallowed. I will therefore set aside the decision of the AAT and substitute a decision affirming the decision to disallow Mr XNPS’ objection, with the intention of effectively restoring the care percentage decision of 3 August 2023, which I note will operate until the subsequent care percentage determinations take effect from 10 July 2023.
DECISION
The decision of the Administrative Appeals Tribunal of 31 May 2024 is set aside and substituted with a decision affirming the decision to disallow Mr XNPS’ objection.