The bill is defined as 23% t.i. so that it gives a clear comparison to the income tax rates - which are also t.i. Had you looked on the AFFT webvsite, there are many, many discussions pointing out that tax exclusive rates (which actually are 29.87%, but many people round them to 30%) are typically used when working with sales taxes.
There are very valid reasons for using the 23% t.i. rate in the bill.
There's no "slight of hand" at all and trying to pretend so is foolish. It's amazing that there are still those who try this after - what - 7 or 8 years on FR discussing this.
Yes, there are valid reasons to state the rate at 23% 'inclusive,' which leads the average non-legalistic cistizen to believe he is paying 23 cents on the dollar when in reality, he is actually going to pay 30 cents on the dollar. Could the valid reason be to make the tax sound more appealing and not as expensive as it actually will be?
Why not just be upfront and openly tell all the actual cost is 30 cents on the dollar? Isn't 'openess' one of the virtuous claims about this taxation? Why the need to hide the actual at the retail counter cost in legalese?