I just plugged in May 2 thru May 12 using Emerald Aisle for a Full size and came up with $299. total
I used the Emerald Club Contract number and the Disney Club coupon.
Do you belong to the Emerald Club? Do you belong to the DC?
I got a rate of $304. using the Entertainment book contract code and coupon.
Rates have been high since 9/11 so your rate is fine for how high rates are now but a couple of years ago, we got a Full size with National for 10 days for under $179 total but that probably isn't going to happen any time soon.