Yeah I was at the Irving show. I honestly think that Scott & STP have their set times booked 45 minutes to an hour after whatever opening act finishes. Because each time I've seen them it's been 20+/- minutes to change the set around and do a quick mic check and then you wait about 40 minutes.
I only think that because at the Irving show he was scheduled for a certain time (I forget what it was at this point, but I was working for K-ROCK back then so I remember knowing when the paperwork said to expect him) and from that time he was 45 minutes late going on stage. But what seals the deal for me is that when he came on, he made some comment about unlike Axl, he'll only make his fans wait 40 minutes.
Even with Velvet Revolver, it was almost like clockwork that an hour after the opening band finished, they'd take the stage. So I really think in their heads it's like 'we're just 40 minutes late' but to the fans, it's been an hour and 40 minutes since the live music stopped.