Matching silver metallic (other colors too) is difficult due to the gun , gun tip , psi, humidity, brand of paint and paint shade variables ...this can be confirmed by the vehicle's VIN number. I am not sure if they still make "Factory Pack's" which is claimed to be an exact factory color mix. In 99% of the repairs blending into other panels is the SOP. Lastly this all can go afoul in short order if the painter is less than skilled. My best "story" ..The VW Beetle is a difficult car to do because of all the radius's which make for a great place to have a run or what we called " a hanger" develop. On a summer night we wet the shop floor down and I painted a red Beetle, after a couple of coats and surprisingly no " hangers presented" I shut the shop lights so as to not attract bugs. Sitting in the office waiting for the paint to tack for a final coat , Larry mentions that the roofer was there earlier and got up on the shop's old roof to an estimate. Right then and there, I hear a bang and that turned out to be a small piece of wood from the roof of the shop landing dead center on the Beetle's hood. ….#@*%! We quickly removed the VW's four 10mm hood hinge bolts, set the hood on a shop cart wiped the new paint away with lacquer thinner and Prep-Sol reshooting the hood......Resale red.