Herman Cain 999 Tax Plan is Flawed

Herman Cain's 999 Tax Plan calls for the following:

9% Corporate Tax
9% Income Tax
9% National Sales Tax

When you add a new 9% National Sales Tax to the
various State Sales Taxes...the net sales in most states becomes
a massive sales tax, for example:

Texas Sales Tax = 8% + 9% Herman Cain Tax =
17% Sales Tax in Texas

New Jersey Sales Tax = 7% + 9% Herman Cain Tax =
16% Sales Tax in New Jersey

South Carolina Sales Tax = 9% + 9% Herman Cain Tax =
18% Sales Tax in South Carolina

Idaho Sales Tax = 6% + 9% Herman Cain Tax =
15% Sales Tax in Idaho

Or does Mr. Cain expect the states to eliminate their sales taxes, which would destroy their already insolvent balance sheets.

Either way, seems to mean this plan either bankrupts the citizens or bankrupts the states.

Am I missing something?
Have any of the debate moderators asked Mr.Cain about this?