You need to create 2 payment terms in this case. Have given the details below:
- Z010: Select day limit 10; Default for baseline date – Doc date; Percentage 2%; Fixed date 15; Additional Months 1
- Z031: Select day limit 31; Default for baseline date – Doc date; Percentage 2%; Fixed date 15; Additional Months 2
Notice that the key fields here are Day Limit & Additional Months.
Hope this helps.