Plugin for Accounting Script -- 2

Hi Guys, I need a add additional feature as plugin to below open source accounting script so it won’t affect the core default programming system. I have done a simple template guide for implementation (See attached) also, an Excel file indicate all feature & calculation (See attached) Some of the feature i might miss out on the simple template guide you may suggest the best solution from your end, overall i want the entire Excel feature to in to the plugin you build. You may use the existing file to modify to make this additional feature as the software plugin. Please review the 2 files & demo of the open source software before bidding. Login into the link below for further understanding below: URL: [login to view URL] Username: demo@[login to view URL] Password: 123456 NOTE: All bidding is final, NO negotiations of 50% upfront or deposit. 100% Milestone sill be release upon my 100% satisfaction once the project is 100% complete with no bug & error.