The two Ts I have worked with pretty much start right on time. We rarely finish on time. I have mostly been thr last appointment of the day. Even when I was not long term T billed for 50 minutes but we always went a full hour if not more.

For me it is helpful because it often takes me a little bit to settle in and warm up. Often we don't really get started until 10 -15 minutes late because I need the time to connect. Also I often need a few minutes of transition in order to be ready to leave. Sometimes that transition can be just a couple of minutes other times it take quite a bit longer depending on how intense the session was.