Thank you for your query at DoctorSpring.com
I understand your concern.
Firstly FBS 95 is normal. HBA1c 6.0 is definitely prediabetic state, a caution to the patient, to get on with the lifestyle modification. I disagree with the doctor's theory of hypothyroidism masking diabetes state. There is no relationship between thyroid and sugar levels.
I will ask you to avoid metformin, wait for 3 months, focus on diet and exercise and repeat your FBS, PPBS, HBA1c, and thyroid profile. Then we can base the treatment accordingly.
Hope this was helpful,