Honestly this sounds like a whole lot of nothing. Three cars at one shop is not a pattern, that is just a slow Tuesday. Paint not matching perfect happens on every repainted panel at every shop in the country, even the good ones, because you rarely get a true match on a factory finish. The blend thing has been going on forever too, insurance has always pushed back on paying for extra panels and shops have always complained about it. Tbh I could go to any lot in any city and find three cars with a door that does not quite match if I look hard enough. Unless the guy showed you actual paperwork where they denied the blend, this is just a story.

Man, finger tight works fine if you actually get it tight with your fingers. The real problem is techs who barely spin it on and call that finger tight. A 7/16 wrench is overkill for most of these fittings, and half the callbacks I see are from cracked threads where somebody cranked it down too hard.