I don't chime in much here, but I've had some issues with this. I'm on 200mg/week. I started with Wal-Mart and would get 4 x 1ml vials a month. About a year or so ago, they switched me over to 10ml vials and told me they were only good for 28 days (sterility reasons). Of course I stocked up! Not long after this, they told me all test was on backorder due to a national shortage... they had run out of the 1ml first, and now the 10's.
I had them transfer my rx to Walgreens and they kept me on the 10's until they ran out. My rx then was switched to CVS and so far, so good. I still get the 10's and although they don't make it readily known, I can still refill every month.
It sounds as though it's hit or miss in getting the pharmacy to ok things. Insurance can be weird too... they cover my Adderall XR brand cheaper than the generic.
Bottom line, if a doc writes for 10ml a month, then the fight is between him/her and the insurance company. The pharmacy can work to facilitate things between these two parties, but they shouldn't question this.
Keep trying!