The difference is likely the dispensing fee. May I ask which pharmacy you use? I've thought about trying Costco but I am at the pharmacy several times per month and the convenience of my neighbourhood Shoppers won out. Even the slightly lower rate at Loblaws wasn't enough to make me switch because I don't find their service or staff to be comparable to Shoppers, which is something I need right now. It hurts to see the difference in black and white though, especially when I multiply it per prescription. Ouch.
I understand what you are saying about knowing/not knowing what to do, I just meant that sometimes I read things and feel like a dim bulb... To be honest, I didn't know anything about the/a formulary until reading this post. My heart is willing to help though, if or when there is something we can do.