I think it's also pretty standard, even pre-covid, for AS to board early and get the door closed at least 10 minutes early, if not more. Combined with the way they block the times, they almost always get in early. I think I had one transcon where we landed almost an hour early and then got to the gate more than 30 minutes late because of ground congestion and their lack of gates (BOS). They gave me a $50 ecert for it without having to ask.

Other than that, I don't think I can remember a time when I got in late on AS - even a couple weeks ago they had to bring a mechanic on after boarding, they still closed the door less than 5 minutes late.

I actually appreciate that they build in a lot of margin - it's much easier to make plans knowing I'm likely to be early than have to figure out realistically how much delay there's going to be due to overly tight scheduling.