Brian,
That's a really interesting suggestion!
When we designed the panel for Blood Glucose Daily Measurements we were primarily creating a mechanism to track time of day when specific measurements were being done.
We do not have a generic element in our data model for the capture of measurement-level notes, which is why this capability is not shown in other panels/measurements.
I have forwarded your suggestion to our development team for consideration in future major upgrades.
Thanks for sending us your ideas,
Support Team