Sandy,
It seems like I remember my guide saying a few months back that Florida requires you to put at least 10% down even if Disney is buying back part of the points. At one time the buyback from Disney could reduce the downpayment, but not now. If the points are $84 and you are buying 150, then the total is $12,600 and you have to pay 10% of this price. Disney will add their amount of $1500 or $2250 if it is HH to the down payment, not the purchase price. Hope this helps.
Becky