The “allowed amount” the insurance company negotiated with the doctor is $150. If the doctor charges more for a visit, you are only responsible for the allowed amount.
If you haven’t met your deductible, you will pay the full allowed amount of $150 and that payment will apply to your deductible.
If you’ve met your deductible, you pay $45 ($150 x 30%), and the insurance company pays the rest.
NOTE: If no deductible applies to a specialist office visit, you will pay the copay (ranging from $20 to $75) instead of the coinsurance amount.