To the extent that a State agency does not pay a claim established under section
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(c)(1) of this title, including an agreement to have all or part of the claim paid through a reduction in Federal administrative funding, within 30 days from the date on which the bill for collection is received by the State agency, the State agency shall be liable for interest on any unpaid portion of such claim accruing from the date on which the bill for collection was received by the State agency, unless the State agency appeals the claim under section
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(c)(7) of this title. If the State agency appeals such claim (in whole or in part), the interest on any unpaid portion of the claim shall accrue from the date of the decision on the administrative appeal, or from a date that is 1 year after the date the bill is received, whichever is earlier, until the date the unpaid portion of the payment is received. If the State agency pays such claim (in whole or in part, including an agreement to have all or part of the claim paid through a reduction in Federal administrative funding) and the claim is subsequently overturned through administrative or judicial appeal, any amounts paid by the State agency shall be promptly returned with interest, accruing from the date the payment is received until the date the payment is returned.