Blood Sugar

I've been therapeutic keto for years. So, I'm not trying to lose weight. I'm very knowledgeable about hidden carbs, etc. So, I think something's missing. Some piece of info. Although I have high enough ketone levels to be considered in ketosis. I also have blood sugars that aren't optimal - upper 90's. It's been this way for years. Stable in that range, but still higher than I'd like.

Only recently have I learned about GKI. This makes so much sense to me and seems to be a part of the missing piece. 

Looking for what could be contributing that slightly higher glucose level. Willing to also consider if there may be genetic anomalies as a factor if you know which one(s) it might be.