They do not carry over. Interestingly though, we just did a split stay and the dining plan from the first stay was still active even though we had checked into our 2nd resort. Which is weird because if you were to check in outright from home let's say, your dining credits are all available the moment you check in. During a split stay, the 2nd portion of your stay's credits don't really kick in until midnight of the day you check into your 2nd resort. Confusing? Absolutely, and something that I was told Disney is working on rectifying. We had 1 QS credit remaining on our plan the day we checked into our 2nd resort. Went to dinner at EPCOT for 2 people - DECLINED!! Our dining credits for our 2nd resort were not active so we had to pay for our dinner. Castmember told me bring my receipt to our resort and explain what had happened. I did and they reimbursed my money. They made it right but it was annoying.