Red75, I relate to what you're trying to say, as I'm DID with one alter. I think the spacey, quiet times are the inner child wanting to come into the therapy, but afraid to, and looking for acceptance from the therapist first. My resistance to going to therapy was from fear that my inner child had, of being judged and preached at like my early abusive caregivers did. I wonder if your T's silence is to allow for your younger part, or parts, to come forth.

But, too much silence feels like rejection, unfortunately. It's very hard for client and therapist to tell just what is needed about dissociation...more talk, or less talk. Maybe you could help by asking T some questions about how she deals with younger parts when you aren't so spaced out. It might help the younger parts who are always listening in to T's intentions.
When I would start to space out, my T would jump right in and ask me gentle questions before I got too far gone. It was always the inner child feeling threatened and me feeling ashamed.
I got thru this impasse in therapy by asking my T what she believes in Transference. I had to know she was accepting of my more dependent inner child and was not going to lecture her about being more independent. My adult self was very critical of my "childishness" but I had to gradually get over that and let the lost little child come up and trust T. Gradually, it was easier to go to therapy and therapy made sense. It isn't a waste of time. things will happen as all of you can feel safe to be in the therapy room. Eventually, your younger parts will work with your adult self better, and free you up to do more things and feel better in life. I hope you won't give up on this very important stage. T and you just need to learn ways, gently, to work together on dissociation in the sessions.