Rexton Revo seem to turn themselves down

I bought a pair of Rexton Revo aids from Costco in August, to replace 5 year old Rexton in-the-ear models. I have a severe loss, but have done well with the old aids. After several adjustments the new ones are also working for me, and the sound is much better.

The thing is, they seem to turn themselves down as the day goes on. In the morning things are nice and loud, but by the evening the sound seems more muted. I play acoustic guitar, and I really notice it then. I have a remote and there is a dedicated music program. But, regardless of the program, even at full volume things aren’t quite loud enough.

However, if I take them out and turn them off and on, then they are loud again!

What the heck is going on?

I asked my Costco audiologist, but so far she thinks I’m crazy and that it is all in my head.