Looking for Adjustment Voucher processing criteria

PeopleSoft 9.2 Image 42

I am looking for a resource that lists criteria that must be met for an Adjustment Voucher to be collected in the pay cycle process.

Modified example: Our AP transaction team entered both a voucher for payment 100.00 and an adjustment (credit) voucher for 50.00 on 12/28. The voucher for payment was collected and paid on 12/29 but the adjustment (credit) voucher was not applied.

Supplier's LOC and Add Seq match. PO # and Line match. Both vouchers show Due date of 12/28 ... we have checked all of the known-to-us obvious reasons why the credit would not be captured but cannot find a discrepancy. Is there a list of all criteria? Maybe we are missing something?