Each contracted plan sets their own rates, that's why.. it could be the "same" company or the "same" prescription plan, but the costs are wildly different from one employer to another. We had a change in our policy last October, where ALL of our co-pays just went up. We weren't warned at all, we just got new cards in the mail. Same insurance company, and otherwise the plan was the same, aside from the increase in costs. My specialist co-pay went up from $40 to $50.. I wasn't happy at all. I pay $55 a month for my Apidra.. and it's Teir 3. A Teir 2 would be $35. Teir 1's are only $10 (and thank goodness most test strips fall under this one). I've stopped trying to use mail order to "save" money - I've yet to place an order where they haven't somehow changed the RX so that I end up getting much LESS than expected. Very frustrating to get straightened out, and they don't seem to get that I'm not scamming them, that I really NEED these things. Personally, I'd rather argue my case at the counter at Walgreens if a mistake is made.. than to deal with it long-distance. Not to mention the savings is really not significant.