Wait, you butted them tight and sanded flat for two whole years? Maple moves a lot with humidity swings, especially here in Oklahoma where it goes from swamp to desert every season. I run about 1/32 on softer stuff like pine and poplar, but maple and oak get the full 1/16 like your lead said.

Man, hate to say it but that load gauge thing isn't really a fair test. Spindle load barely moves on a lot of machines when you're taking light passes, especially in aluminum or with a small chipload, so the needle sitting still doesn't mean the machine is happy. The chip on pass 3 might've been the insert rubbing or a bad spot in the material, and load wouldn't show that at all. Sound is honestly the better tell for stuff like that, you hear the pitch change before any gauge catches it. So you're not weird for closing the door to listen, you're just using the tool that actually works for that job. The guy in Denver made a bad call trusting one number, but the gauge wasn't lying, he was just reading the wrong thing.