Correct! You are typically responsible for the list price, not the net price the payer pays.

So, you pay $300 for the drug (list price). The insurance company uses that $300 to pay the drug company, which in turn, rebates $150 back to the payer. Pure profit!

If you are just responsible for the co-pay it works better. You pay $30, the payer pays $270 and the manufacturer rebates $150. Overall, the drug costs $150, $30 coming from you and $120 (net) coming from the payer.

I'm not sure that's true. In cases where I've had a deductible, I've always paid the lower negotiated price. The vendor (doctor or pharmacy) has always run the product through insurance first, then billed me whatever my insurer says is correct.

It's really up to the payer as to how much you are billed. I have heard of them passing along the negotiated discount, but it doesn't always happen.

what you pay for advair should have little / nothing to do with your plan deductible. you should still get a negotiated, lower than retail price for drugs.