willowmena,
personally, I trust the bone markers. My suspicion is that you'll see improvement on the next Rems. I read that it is important to complete the two years of Tymlos. My thinking is that because Tymlos works carefully, removing older fissured bone, and replacing lost collagenous structure before adding bone mineral, the density or mineral content is added more slowly.
You might consider the biomechanical CT for your next scan https://ondiagnostics.com/
Medicare will begin paying for this scan in lieu of the dexa this October.