Does it follow then that he's proposing we also eliminate medicare/medicaid payroll deductions, and roll that into the one rate?
The text says it eliminates the payroll tax, so that's the 6.2% for social security and 1.45% for Medicare (for the employee). This is one of the main differentiators of this plan compared to other flat tax proposals. Eliminating the payroll tax and the first $50k income exemption are what benefits the median US household, which has an income around $50k. This means that median household pays $0 taxes based on income with this plan compared to roughly $6200 (12% of income) currently. This is a 100% savings on income taxes.
Here's various savings based on some income amounts:
$25k income: 8% taxes now, 0% taxes with Rand = 100% saving
$50k income: 12% taxes now, 0% taxes with Rand = 100% saving
$75k income: 16% taxes now, 5% taxes with Rand = 69% saving
$100k income: 18% taxes now, 7% taxes with Rand = 59% saving
$125k income: 20% taxes now, 9% taxes with Rand = 56% saving
$150k income: 21% taxes now, 10% taxes with Rand = 54% saving
$175k income: 22% taxes now, 10% taxes with Rand = 53% saving
$200k income: 23% taxes now, 11% taxes with Rand = 52% saving
In order not to tax the first $50k they're either
1) going to not withhold for the first part of the year, meaning that after I hit $50k I will start having withholdings, which I am totally not cool with, or
2) they're going to have to charge 14.5% all year, and if I have (for example) a $60k salary they'll have to withhold $8700. But 14.5% of the taxable revenue is only $1450, so they'll have to refund me a whopping $7250, which they've drawn interest on all year instead of me doing it.
There won't be much change in how much is withheld each paycheck in that employers already handle exemptions/deductions based on the allowances people file on their W-4. I.e., there will not be a jump in take home pay because each paycheck's withholding already factors in the "first $50k tax free."