Subsequent Debits/Credits: Examples

Invoice as subsequent debit
Purchase order: 100 pieces of Material A at $10/pc
Goods receipt: 50 pieces
1st invoice:
50 pieces at $10/pc. = $500
2nd invoice
Unforeseen costs: $50 for 50 pieces
If you do not post the second invoice as a subsequent debit, the system would assume that you have received another invoice for the purchase order (you would, however, receive warning messages due to quantity and price variances). If you post it as an invoice, the quantity update for the purchase order would be incorrect; the system would update the invoiced quantity to 100 pieces.

Credit memo as subsequent credit
Purchase order: 100 pieces of Material A at $10/pc.
Goods receipt: 50 pieces
1st invoice:
30 pieces at $10/pc = $300
2nd invoice:
20 pieces at $11/pc = $220
Credit memo:
Invoice amount too high by: $20 for 20 pieces
If you did not post the credit memo as a subsequent credit, the system would assume that you are entering a credit memo to cancel an invoice document. If you post it, the quantity update would be incorrect; the system would update the quantity invoiced to 30 pieces.