Well Tim, that is something that comes with a lvl.3 finish and painters have to accommodate that as well. The texture between the mud and drywall changes when you sand and it also depends on how much you fur up the drywall from rubbing it. If they don't want to see the difference then do a lvl.5 finish and charge them more. Critical lighting is also an enemy of ours that makes a job different from the next.But if the painter doesn't use a quality primer or enough primer, your mud will flash through the finish. And this stuff helps eliminate that. Am I the only one on here that has joints flash through the paint? So many times the joint isn't as shiny as the rest of the wall. N/M has eliminated that for me. The painters have noticed, too. And I didn't have to do anything labor intensive beyond dumping a couple ounces of stuff in a five on the skim coat.