It's probably complicated by the fact that I'm a minor, but I looked into a transgender specialist in Boston I think who required the equivalent of 12 months of therapy at 2 sessions a month. The physician I chose instead asked for 6 months I believe, but was also willing to replace it with some sessions with an employed therapist at the clinic. I don't know how you guys are getting T letters so fast, but it's good to hear.
It also varies with therapists, mine hadn't had a transgender client before so he needed to look into the standards of care and such. I've been seeing him weekly since February and am only getting a T letter by next week, but I also have dozens of other issues that we've been focussing on rather than gender.
I've heard you're supposed to be on T for a year before getting top surgery so there's no risk of regrowth and so the surgeon can get a better contour working with male muscular structure and fat distribution. So therapy sessions might not be what takes the time.