the awami love of jenwan paint is completely off the hook nuts and stupid, The used car dealer will always try to steal from you no matter if you have an unused car.
Good that you are refinishing the whole car, its the correct way to do it. No-one likes to drive around in a deadbeat, dented, scratched up and faded jenwan paint car. ask your painter to dry sand it first, then wet finish it till 1500 grit paper, rub down with degreaser cloths and then paint and seal it with everything removed. when done, wet sand it again with 2000 grit paper slightly and buff some proper glaze onto the car, top off with a synthetic wax coat applied about 2 times and admire the glass finish.