I think I have read the fare requests are handled differently. OBC is simple and done... I turned in 75,000 as well on my cruise in 3 months. I have paid the cruise in full (discount included). My credit card still shows the 75,000... both my TA and RC say I am paid in full. I just assume at some point in the next 2 months they will disappear.
I also have OBC to add in rewards, and my parents want to give me OBC from their credit card rewards, haven't figured out any issues or problems that may or may not cause.
2013 - Majesty of the Seas / Bahamas (May)
2012 - Freedom of the Seas / Western Caribbean
2011 - Radiance of the Seas / Western Caribbean
2009 - Enchantment of the Seas / Western Caribbean
1999 - Rhapsody of the Seas / Southern Caribbean