My T is extremely consistent with time and my sessions are 50 minutes. In the 2.5 years that I’ve known him he has always started exactly on time. Once or twice we’ve gone over by a couple of minutes, but that feels uncomfortable to me for some reason, so I keep a close eye on the time and make sure that we end on time. Not sure about your T, but with my T if he was late or just changed the way he started or ended sessions it would be perfectly ok to bring this up and talk about it.