Ok, i have completed the transaction and here are the results.

1. i used 18500 miles from american
2. i got a budget car for 9 days in austin tx over the thanksgiving week
3. the pdf from aadvantage said 'paid in full' but the fine print says 'except for taxes and fees.'
4. the budget guys warned me 126$ after i drop off in 9 days
5. they were right. here is the breakdown:
a. 26.14 11.11% fee
b. 3.50/day cfc 31.50
c. 2.25/day vlf 20.25
d .56/day erf 5.04
taxable subtotal 82.93
tax 15% 43.94
total charges 126.87

concession recovery fee
cust facility chg
veh license recoup fee
energy recover fee

they guy at the budget counter said 220$ was the cash value of the 18.5k miles from budget's perspective.

i wish there was a way to pay 100% with miles even if it took more miles. i have more miles than cash rite now.