That's only one third of what will be determined to set the rate. With the other two be variables, you are leaving the tax rate open ended to greatly exceed the much loved 23% "inclusive" (30% sales tax at the counter) with no caps on spending.
Try reading something besides the propaganda you are being spoonfed. This reads like something right out of the Watchtower.
Are you completely unable to comprehend D. R. The two parts you refer to are the entitlements of S/S and M/C which are controlled by totally different laws from the FairTax or any tax law.
In the bill- if you'd read it with any understanding - the funding amount for each are expressed as a percentage so that it may all be handled as a single rate external to the bill. The General Revenue Rate (14.91%) is the REAL FairTax rate, the other two parts are the existing entitlements - which means that, together they now run you about 8% on a tax inclusive basis. That's way too much AFIC. But the tax bill affects those not at all.
It's worth pointing out, too, that those two rates (as well as the General Revenue Rate) are as likely to go down as up; probably more likely to decline actually when the FairTax gets into operation. The only "open ended" thing are the two entitlement themselves, not the FairTax.