Take your car to the body shop at the dealer. They'll be able to give you a much more accurate assessment. Not that your detailer is lying, but chances are the painter at the shop will have a better idea what has happened to the paint, and whether it is salvageable. Sanding a car down and re-clearcoating IS repainting a car. If the car is already sanded and masked to spray clear, it is in the painter's best interest, generally, to go ahead and put a light coat of color on the car. Otherwise, imperfections that may not have been visible under the damaged clearcoat WILL be once the car has regained it's luster.

Smoke silver is a tough color. If you opt for a re-spray, take it to a good shop!!

Jay.