That is so weird that you say that because today I booked priority seating for CRT and I will be there on April 13. That is more than 180 days. In fact my 180 will be on October 15. Here it is a week earlier and they booked it. They didn't even check my reservation, they just asked me what resort I was staying at and that was it. So to answer the OP's question, I think that it is 180 days PLUS the number of nights you are staying. For example, I am staying 7 nights total. According to my own calculation, I am at 187 days from my CRT reservations, even though the reservationist didn't ask. Maybe she found me by my name or phone number, but it didn't seem like she verified much.