Hi there -
The app calculates the A1C using the standard formula via the ADAG - http://professional.diabetes.org/diapro/glucose_calc
As far as personal experiences, others can answer that, but we thought it may help to know how it's calculated.
If you need assistance with the app at any time, tap on Support in the menu on the left side of the app, and send us an email. We'll be happy to help.
Emily