Dr.AddMedPHL said:It helps to say which part of this you are uncertain about.
There is a second half to this that has not been said yet. Whatever the answer turns out to be, the method for getting there is the same: state the assumption, do the arithmetic in public, and invite the correction. That is slower than asserting, and it is the only version that survives being wrong.
Correct me if the detail matters more than I have assumed.