Then answer to the asker.
No, that makes it wrong as a formula (look how it looks like). It is good for estimation and maybe simulates salaries pretty well but it is surely completely different from the real formula which is used.
but the final results are pretty good, and this seems to make it reasonable that ID is predited another way for a center then for a PG elsse you would notice the difference in their salary.
I have this salary formula in a excel sheet, and i noticed many NT candidates in it the last season and even the position switched only appearing when the salary is pretty close to another - so you use mostly the highest salary to determine the position.
And the same goes for the cap, which seems to depending on Position too - because Centers with low secondary(or tertiary Skills), reach their cap on a similiar level then guys with good secondary and tertiary skills. I don't expect that the potential formula is similiar to the cap formular, but they ain't totally different.