I have an update. As I reported, it was at 86% yesterday morning, down from 93 the night before, which is not good. However, I used it yesterday (maybe 3 hours) and at bedtime it was only down to 83%. This morning it is at 82%. Sooooo, it does seem that it stabilizes after awhile after a "topping off." I actually wish it would be good or bad, not this inconsistency.
I think that it is now working OK and it will take me another 3 weeks to drain. The problem now is that I'm afraid if I return it while it is working OK, they'll say there is nothing wrong with it. I guess I'll have to wait now till it drains, but then I'll recharge it, and then let it start to drain for a few days and then return it while it is misbehaving. Such fun!