Been in contact with Furen/Steve once again. He's upgraded his legendary calculator, however I didn't provide him with enough information for it to be completely correct (I forgot how the rounding was done for the spreadsheet). Still, it is pretty close:

Calculator

Does anyone remember how the rounding was carried out for the formula? Was it add all the modifiers up then round down or round the modifiers as you calculated them? Also anything else I should be telling Furen/Steve for the calculator to be more accurate?