We have EA and DC and the lowest they quoted me (this was a year ago) was $178 for April 12 week (through 800 number as I was having such trouble booking it on-line), so to answer original question here, yes, I had trouble with coupons/discounts trying to book on-line.
Tried to use DC coupon at the time, but it is expiring April l, 2002 so I couldn't. Now a new DC coupon comes out, (exp.l2/02), so I called National to try to use it towards my existing ressie, and she said, no, they have to start all over and re-book it to use the coupon. Then she told me to just keep the $178 rate because it would be cheaper than re-booking at today's rates. Oh, well!