I've been doing waking (or more precisely "just after first wee") testing since 01 April 2020, and still can't see any rationale
Basically I think
4s rare, but nice
5s good
6s OK
7s hmm, is something going on?
8s check for infection/illness
I'm mostly 6s, and that's seems OK. I am due an hba1c soon. I just can't worry about daily variances, there's not enough time and too many variables that can affect it eg
Sleep, quantity and quality
Exercise, quantity and intensity and duration
Food
Medication
Stress
Temperature
Alcohol
Genes!
And probably more.
Too many for my little brain