What's your celestial? There's an interesting old thread on here about metaformin
http://www.diabetes.co.uk/forum/threads/type-1-and-metformin.29433/ which is worth a read. I have heard of this before but find the idea a bit odd. If you are suffering from dawn phenomenon (most common cause of high blood sugar on waking) then trying different basal insulins, switching the times you give them and pumps are all things people try. I can see why a prescription for metamorfin would be preferred cost wise over a pump though......
Are you considered insulin resistant? If you are it's always worth trying a different insulin to see if your body reacts differently. There are a lot of different ones out there and the newest are not necessarily suited to everyone.