A while (few years) ago I was going to school only a few hours a day in a special care-class in a special education school. When we were evaluating I was expecting them to say "You're doing well with this few hours, let's increase your school hours". Instead everyone was like, this is going well and don't mess with success. So I didn't have to go to school more hours. It's very much possible your T will think similarily and not increase the time between sessions.