Discount Formula Question
 

I worded my previous post incorrectly - what I am trying to do
is give a sales rep the option to either put in a % discount, or allow them
to enter a FINAL price without them having to calculate. For example, an
item listed at $20,000, and they want the final price to be $17,500. How can
I let them either say "I want a 20% discount, or I just want the price to
"end up" being $17,500. Thanks.