Leslie is right with her setup. If you set the payment term as follow this should work:
Due: Net Days, 30
Discount: Date, 10
Discount Type: Percent, 2
This should work. However, your problem is that GP only supports one payment term per document, so if you assign the 10th as a discount date, you will not be able to assign the 25th to the same document. The vendor is doing this to be fair to customers who buy on after the 10th of the month, but before the 25th (only so, this would make sense). So, here is what I suggest:
1. Setup both payment terms: 2% 10th NET 30 and 2% 25th NET 30.
2. Like the trigger in article, set a SQL trigger on PM20000. You will want to create the logic to assign the proper payment term and calculate the proper due date and discount date based on the invoice date. So, for example,
Invoice date: 6/25/2010; Due Date: 7/24/2010; Discount date: 10th
, would get assigned the payment term of 2% 10th NET 30.
Invoice date 6/10/2010; Due Date 7/09/2010; Discount Date: 25th
, would get assigned the payment term of 2% 25th NET 30.
So, it's safe to say that any invoice dated from the 25th of the month of the invoice and the 9th of the following month would get assigned the 2% 10th NET 30, and any invoice dated between the 10th of the month and the 24th of the current month, would get assigned the 2% 25th NET 30.
As I said, you may be able to do this with a SQL trigger.
However,