Why would you lap the rings if you don't have an alignment problem to begin with? I assume that the rings were checked for alignment before the optics were attached because there is more to mounting a a scope than just slapping it in the rings & tightening the screws. The lapping is done after the check, not before and only if there is some sort of problem. It is not SOP and shouldn't be. It's a procedure used to correct a specific issue.