Taxation Administration Act 1953
The Commissioner may, in the manner he or she determines, apply the amount against a non-RBA tax debt of the entity or, if the entity is a member of an RBA group, against a non-RBA tax debt of another member of the group.
(a) a tax debt that has been allocated to an RBA; or
(b) general interest charge on such a tax debt;
the Commissioner must then also allocate the amount to that RBA.8AAZLB(3) [Excess non-RBA credit]
To the extent that the amount is not applied under subsection (1), it gives rise to an excess non-RBA credit in favour of the entity that is equal to the part of the amount that is not applied.8AAZLB(4) [Balance adjusted]
The excess non-RBA credit relates to the RBA (if any) that the Commissioner determines and the balance of that RBA is adjusted in the entity's favour by the amount of that credit.8AAZLB(5) Separate RBAs for one entity.
If the non-RBA tax debt mentioned in subsection (1) has been allocated to 2 or more RBAs, the Commissioner must allocate the amount applied between those RBAs in the proportions in which the tax debt was allocated.
Separate RBAs may be established for different businesses or undertakings conducted by the same entity, for different parts of the same business or undertaking or for different periods: see subsection 8AAZC(5) .