My boss has been begging me migrate a nightmarish complex excel report he made to calculate the payout of a tiered rebates program with compounding rewards. Today I finally decided to make take the time and I sat down with him so he could break it down for me...

Me: *looking at the mess of formula's* it would be easier to rewrite the math than decode this - can you just give me the reward rules... where does that value in cellX come from?

Him:*pointing at the spreadsheet* There! All the rules are in there for you :-)... like it's some big favour...

Me:No I mean when you wrote this, what did you base this off? There must be something...

Him: *Very Gravely* No, no, no it's far to complex! It took me ages to get this sheet right and it balances so just trust me and use it ok?

At this point I will mention he's an accountant so yeah I fucking trust him... fast forward past 15 minutes of digging through what may as well be quantum theory and lo and fucking behold all 2 sheets and 100 calculations are mathematically fucking pointless. Aside from formulas like this:
$X10=+(((O10+P10)-((O10+P10)*$X$3))*$R$4)+T10
which is actually equal to (X10/R4)/L10.

Anyway once you compound and sum the "tiered" benefits the rewards payout is ALWAYS = customerSpend*1.81.

This is why programmers name variables.