I spoke to someone last week also about entertainment rates. I asked why discounts are released for what seems like every week but the one I want to travel (March 31-April 7). Apparently the computer generates the release dates for discounts. It goes back and looks at the occupency rate for the same week last year. If it was really busy then, it takes it's time releasing the discounts. The problem with that system is that Easter week this year was very early (the end of March), but does not fall until April 20th next year. I was reassured that the "error" in the system would be spotted and discounts would be released at a later date. I was also told that there are tons of vacancies for that week right now, so one would assume discounts will be offered to fill up the rooms.
Another point on the minimum night stays. I also have 4 nights booked at the PBH but was told I could only get the fan club rate if I stayed 5 nights. I booked 5 nights, and called back 2 days later to let them know I couldn't change my flight. They dropped the 5th night from my booking and still gave me the discount. I don't mean to encourage people to "work the system", but in my particular case, it made no sense for them NOT to do that. The 5 nights at the cheaper rate was less money than 4 nights at rack. I was bound and determined not to pay a cent more than I had to, so I would have paid for the 5th night if need be. This way, I get my discount, and they have their room to rent out to someone else. Do the math. If paying an extra night at the entertainment rate is still cheaper than 2 nights at rack, book it and then see if you can work something out later on. The worst that can happen is that you go back to your original 2 night ressie at rack rate.