We have 2 companies for which we use delivery based invoicing. Both companies use same order- delivery and billing types however for one of our company the invoice is generated with a wrong assignement number (being the shipment #). As per our configuration, in the copy control to billing the setting is E = billing doc. (no u-exit or any sort of customization).
The only difference between the companies is one is using the transportation module and the other doesn't. The issue arises with the one using the transportation module. The item sold can be the same in both company and are both ZTAN . This causes issues for our collection dept. as they use assignment number in the FI document being fed by the billing doc. to reconcile the multiple partial payments we have in our industry.
Note that this is not related to the GL account settings such as the FSG, both are using the same with same settings.