I took it for its effect on HHV-6 specifically.
Good point. Valcyte does have some activity against HHV6, but it's not as strong as it is against HSV, VZV, CMV, or EBV. And since there's little else to treat HHV6, it is often used for HHV6.
This is not true. See Dr. Prusty's papers.
Dr. Prusty's papers refer to a more subtle type of reactivation, which is distinct from pure latency. I think what you're getting at is that this more subtle type of reactivation will not lead to changes in antibody titers in the same way as a full-scale reactivation would.