The amount of the earnings withholding shall: be enough to pay the support and any arrearage included in the payments required by the support order; and include any arrearage accrued since the support order. When arrearages under subsection (a)(2) of this section are part of an earnings withholding order or earnings withholding notice, the total arrearage withheld shall be in one lump-sum payment or apportioned over a period of time. The amount of the arrearage withheld under subparagraph (i) of this paragraph shall be determined by the tribunal or, in a case in which the Administration is providing support services, by the Administration. The amount of arrears under subsection (a)(2) of this section apportioned to each payment shall be at least $1 but not more than 25% of the current support payment. If there is more than one earnings withholding order or earnings withholding notice against a single obligor, the Administration shall allocate amounts available for withholding, giving priority to current support, up to the limits imposed by the federal Consumer Credit Protection Act.