Yellowing/163 C

Maybe a silly question. I read somewhere that yellowing begins around 163 degree C. I’ve found it to be pretty true. If I forget to mark “yellow” can I go back and find where the 163 threshold is and mark it accordingly? Anyone else see this to be pretty accurate?

Judging color is too subjective for my taste, I’ve convinced myself the LED light which illuminates the beans thru the glass window likely has too much blue-weighted spectrum to make the guesstimate rational. So I took the cowards way out and settled on 330°F/165.6°C as the Yellow point and I mark that temperature as the color event. Works for my purposes but then I’m roasting the same variety most of the time. For decaf it’s a lost cause. And as usual YMMV…