Sure can, if everything blocks out without going through to filler anywhere. After 180, I would apply guide coat again to make sure those scratches are completely gone. Going from 180 straight to 400 is a pretty big jump, but it can be done. I usually go to 320 first, then finish with 400-600, depending on color.I’m happy with were it’s at, but like you said, light grey doesn’t show much. I’ll take your advice and block sand the whole car with a guide coat once I take care of the fender. Can I not go straight to sealer from the blocked 2k if I take it from 180 to 400?