We had a volume discount working on previous oscommerce site but lost this function after upgrade 2.3.1. Currently it only has a 10% off discount.
We need to add this progressive discount: [url removed, login to view]
We can grant access to old site so you can look for code. We think the code is something like this but we do not know where to put it: (2-5:10, 6-10:20, 11-15:30, 16-20:40, 21-x:50)
We are also looking for an oscommerce expert to help with other issues. We manage over 300 websites.