Hi John,
I'm happy that your issue is fixed.
Answer to your question is yes, the effect is that, only customer has to enter the base line date at document entry level, if you select "No Default" in OBB8.
Payment Method Supplement is used to grouping of open item for different purposes.
Payments are separated according to payment method supplements and can be printed separately by these supplements or sorted by them for printing.
Items with different payment method supplements are settled individually. When printing a form, it is possible to print separately according to payment method supplement. Checks can thus be divided into several groups that are then subject to a number of different checking procedures in the company before being mailed, for example.
I hope your issue for multiple check printing as per document date is resolved, and Payment Method Supplement is not your customer requirement, then don't use it. and this has nothing to do with multiple check printing by document date date.
Regards
Javed