So, with fairly extensive testing (see a total of 8 hours spent trying to do a simple division calculation) I've found that division of pulled attribute values doesn't work, at all, and multiplication is excruciatingly unreliable (the same multiplication of *2 has only worked in one attribute calculation, but past that has needed to be coded at attr-y + attr-y to work around multiplying it by 2) Doing slight tagging tweaks to the code to make it compatible in javascript testing sites yields the appropriate result. This means it is a bug within roll20 it's self not allowing certain calculations at all within the sheets gm's code in.