Here is another data point.

My Offer:
Earn 35,000 bonus points after 20 paid nights. Earn an additional 15,000 points after 25 paid nights (for a maximum of 50,000 points).

My Stats:
BIB nights this year: 134
Rollover Nights: 35
Total: 169
Fall Megabonus: Complete for 50,000 points