I'll take a stab...

Your TA PS % is too high. $600M is too high. (definition change) The PTIX should be less $231M Management Incentive plan times whatever increase you think management will get for their performance in a year where they make $6B. Let's say it's a 30% raise. That would make PTIX $6B-($231Mx130%)=$5.7B. This means $570M PS.

If we get a raise of 14-21%, the wage pool increases by that amount for at least a third of us. But your wage pool is too low. It's closer to $5.5B. 1/3x$5.5Bx121%+$5.5B=$7.7B wage pool (for 2018 as an example)
$570M/$7.7B=7.7% not 15%
It's even less if the other employees get a raise.

So your 15% estimates for TA PS are too high.

Also, $950M/$5.5B=17.3%. So your C2012 PS is too high as well.

As a fact check, in 2014 we had a PS% of a little less than 17%. That was with a PTIX of $5.853B (before adjustments it was $4.5B as reported by press)

You may want to re run the total compensation numbers using a wage pool closer to actual. $4B is too low.