Forty five minutes? That is a crazy amount of lid opening. Every time you open that thing you dump heat and add time to the cook. The guy was not wrong about your arm either, that is a lot of walking back and forth for nothing. Once that bark sets you are just drying it out by messing with it. A judge told me something like that once about not saucing too early and it stuck with me the same way.

The "too proud to admit" part is the whole ballgame. I stopped asking if they installed it themselves because nobody ever says yes, so now I just look at the wiring and you can tell in two seconds. Zip ties on the keypad power, ground wire wrapped around a screw, sensor stuck up with double sided tape from the dollar store. Nine times out of ten that's your trouble, not the panel. Power surges finish off the cheap keypads fast, but the DIY job is what put them there. I just fix it, hand them the bill, and let the silence do the talking.