Borderter, it's not an area I have experience or much knowledge in, and I imagine you might have been quite surprised about the turnaround in approach.
In your shoes, I'd be inclined to either go back and ask about it, or if you have email contact, maybe ask that way? I'd be interested to know what has brought about the change of heart, and ifit is guidelines or scientific papers, I'd be asking for links to those, to do my own reading.
Have you been given a prescription for Metformin, or is it just a suggestion at the moment?