The bill calls out the marginal tax rate (just as do the present income tax tables). It requires the receipt to specify the tax paid at point of purchase using the inclusive marginal rate of 23%.
If you paid the doctor $100, then $23.00 would show as the marginal rate which is what you would pay at that point in time - HOWEVER you would be receiving a refund so that (using your 10% effective tax rate) you'd end up paying a net of 10 percent tax inclusive after the prebate. The untaxed doctor bill would be $77.00 ($100.00 minus $#23.00) making the effective amount you pay while considering the prebate to be about $85.56 - the $77.00 plus the tax amount to include your 10% effective rate.
Excellent! So, a bill that is $100 before the FairTax would rise to what level after the FairTax is added?