So a little confused, 1) should check_confirmation appear the same as checkout_payment?
2) Does checkout_payment not reflect the prices requested to be shown?
3) Was the goal such that the price displayed always remain the same but that tax was to be calculated for everyone? (If this last one is true then probably need to modify the tax calculations to not be excluded when the wholesaler is making a purchase.)

May also help to use a sort of example product to describe what is desired for each page and compare that with what is happening. Use very simple numbers like a product cost of 100, a tax of 10%, a wholesale discount of 20% (this way the numbers are not expected to be confusing.)