Make small modification in a PHP plugin

Hello! I have a small problem regarding a plugin for the excellent php shoppingcart "[login to view URL]". This plugin allows Couriers to be set up with banded charges depending upon the number of items in the basket or the value of the basket. (courier charges = shipping costs) But it has one limitation: "Banded Couriers" is based on the principle of diminishing costs, ie. the larger the order the lower the courier charges. If you have courier charges that increase with order size this plugin WILL NOT WORK for you! That's my problem! I need to have this plugin with courier charges that increases with order size. Here is a description of the plugin: <[login to view URL]> Here is the download (only 16kb): <[login to view URL],download/filecatid,56/chk,d1b5619e747dddd6dd428ee9d5900360/>[][1] And here's a link to the [login to view URL] (if you need it): <[login to view URL]>[][2] ## Deliverables 1) Complete and fully-functional working program/plugin in a usable or working form as well as complete source code of all work done. ## Platform Same platform requirements as Quick.Cart.