Terms of payment configuration.

Hello,

We have a request from client to configure two terms of payment and below is the rule for them

8% 10 EOM : 8% discount if payment made in 10 days of shipment

If we ship goods on or before the 20^th of the month, the due date is the 10^th of the following month. Ship 5/15, Due Date 6/10

If we ship goods the 21^st through the end of the month, the due date is the 10^th of the following month. Ship 5/25, Due Date 7/10

10.76% 10 EOM : 10.76% discount if payment made in 10 days of shipment

If we ship goods on or before the 20^th of the month, the due date is the 10^th of the following month. Ship 5/15, Due Date 6/10

If we ship goods the 21^st through the end of the month, the due date is the 10^th of the following month. Ship 5/25, Due Date 7/10

Ship date is being invoice date (Since we bill customer right after shipping)

I tried day limit value 20 & 31 for same terms of payment as well as baseline date calculation but did not work. Is the condition for due date calculation possible in SAP ?

I was able to get discount calculated correct but in second line if i try to keep any specific day for due system gives me an error with message of Day limit can not be set.

Please help

Thanks