Custom coding on current script using Smarty

Currently running a network of site located at [login to view URL] and [login to view URL] and so on. They all run on the same script, shared admin panel. So, only one part would need to be modified. It runs on PHP but, it is entirely encripted so the Smarty files would be the ones needed to be edited. We need 2 things done. 1. We run a cash back based site at [login to view URL] Currently it only allows for us to offer our members a $ amount to earn. We would like to be able to offer both a dollar amount as well as a percentage. So, lets say our advertisers pay us 15% per sale. We would need to be able to offer our members say 12% cash back on their purchase. The entire process is mostly automated, and would need to continue to be so. 2. On our referral based sites, such as [login to view URL] we offer our members the chance to earn from their referrals as well. We currently offer 10% earnings but, the way it shows in our members accounts is just that their referral have referred someone. We need it to show how much they have earned from their referrals, as a dollar amount.