Honestly a caliper doesn't tell you the actual cut width, it only measures your blade stack. The real test is a test cut on scrap, since the arbor and flange slop can throw things off by a few thousandths.

The "casually said" part is what gets me. They never sit you down for a serious talk about it, they just drop it in the middle of a normal appointment like it's nothing and then you think about it for three weeks straight. I once had a lady tell me my part line was "a little enthusiastic" and I laughed it off, then went home and stared at the ceiling wondering if I'd been scalping people for a decade. Turns out she was right and I was basically starting every part with a dull machete. The worst part is these offhand comments from sweet old ladies are always the most accurate feedback you'll ever get. They've been getting their hair done since before I was born so they know what a good service feels like. Any random stranger can hand you a gold nugget without even trying.