The Genuine Toyota Extra Care warranties do not allow for a full refund at any point after the initial 30 or 60 day period. They do, however, allow for a pro-rated refund at any point.
The dealer's method of a full refund on the extended warranty is for a third party policy, which is a policy I'd avoid to begin with. I have been told before that when the full refund promise is made, it is the dealer who is "insuring" the policy, so to speak. I am not sure how it exactly works, but it is not a risk I'd want to take in case the dealer goes bust.
Besides, genuine Toyota policies are the only way to go as they give the dealer more control when it comes to approving warranty claims. You can buy them for about 1/2 price from sellers such as warrantyshack.
On my Nissan, I bought my 8/120k Nissan Security Plus Gold Preferred policy for about $1145 from an online Nissan warranty seller-- $850 less than what the local dealer wanted.