The mystery of the higher preshots!
Do you want to try a snack at +9 to see if they come down? You could start by trying in the AM cycle so you don't have to lose sleep.
There is one variable you haven't tried, Robert, and that is to feed a slightly higher carb food than you have been. Would you consider going to a food that is higher than 2% for a little while? A little light reading for you: https://www.tapatalk.com/groups/fdlibrary/low-carb-vs-lower-carb-t18.html#.VGZnufnF-Sp