It looks comuter generated!

Sorry man.. it doesn't speak to me. I think your whitewash is too gray. It looks more like primercoat to me or a tank that was burned. They really whited those puppies out back then. The coats were thick and applied multiple times. You're on track with the weathering I'ld increase the white a little on the turret and take a bunch off the back deck. As vehicles sat still for hours and days, they would get covered by real snow. The heat from the engines would melt the snow thus washing off most of the whitewash on the rear deck. I'ld also apply some rustinng around rivet and joint areas. Somewhere I've got a picture of a King Tiger someone in Dallas did in winterscheme that looks well weathered unfortuneatly it wasn't on the digital and would take hours to find. I'ld consult one of those Squadron German Armor books they show some excellent white washed vehicle paintings to give you some ideas

EXCELENT WORK IS VERY NICE - CONGRATULATIONS
ROBERTO