I would throw the timer at T. lol

Seriously you should straight out ask him, "What the hell is with the timer?" What do you think has kept you from asking so far?

I hope I am not being obnoxious (I'm not trying to be) when I say that by the sound of your post, it almost sounded as though you were reducing your sessions more for your T than for yourself. Have you spoken with him completely on this subject? I think the idea of having control would be for you to say what you really think-- and don't ever let him think you are ready for something if you are not. I'm not saying you aren't ready-- only you would know that. I just hope that the two of you explored it.