Alter formula to get sum without any value being less than zero.

My goal is to find the % rent for each month to equal $36,868 without a month being negative, like you see in columns Z and AA

What I'm trying to do is calculate what the rent would be over the Breakpoint (if you look in line 8 you will see the example in yellow that I'm trying to solve. in columns Z and AA I need the numbers to be positive... while the AG still calculates to the 12% over the breakpoint.

For example, 1,121,616-814,382 = 307,234

Then 12% of that = is 36,868...

My goal is to find the % rent for each month to equal $36,868 without a month being negative, like you see in columns Z and AA

Is there a way to alter the formula of cells U8:AF8 in such a way that no value is less than zero and the total comes out to 36,868 (12% of T8-C8).