没有朋友帮帮忙，出出主意吗？

Your model is not fair.
It is complex.
I wish your store heads understand what your formula means.

In order to get your job done,
you'd better make the following items clear,
1. why the sales/task ratio is so volatile:  from 44% to 177%?
2. why there are five variables in your salary formula?  to show the designer has a math ph.d degree?
3. last but not the least, your data indicates that all your employees' salary are going to be reduced, no matter what, the amount is from -240 to -2967.

Let me tell you something buddy,
whoever delivers the upper proposal is destined to fail, no one will agree with you, (unless you are a boss).

Here is my suggestion,
First of all, make sure your final simulation is no less then your former salary. (meaning at least equal.)
Second, get your performance compensation formula simple and straightforward, let your employee know what it means at the first glance.
Thirdly, tell your boss to set the goal realistic.

I hope it helps.
Good luck buddy.