This is an adapted presentation from one of lab equipment manufacturers and the only one that I've come across that gives sensible reasons for switching to the new HbA1c range.
It sets out the changes, the reasons behind those changes and has a conversion chart.
All someone needs to do is write a short programme that will convert one figure into another....
... on the horizon, which might change this is the idea of estimated average glucose (eAG) analogous to eGFR to be reported alongside the new HbA1c. Watch this space.