You do get points/elite night credits on LNF rates.

LNF=lowest night fare. Pretty much, if you can find a lower rate on a competing site, ie orbitz, then you get the lower rate and an additional 25% off.

I usually start on a site such as www.kayak.com which compares multiple travel sites including marriott.com. If I find a cheaper rate, then I book the room at marriott.com the complete the online claim form. Usually you get an email within a couple hours saying if it was successful or not and if so your revised rate.

The lower fare needs to be for the same room type, same cancelation policy(ie fully refundable), publicly available rate(no corporate code, MR rewards rate, AAA etc...)

Some wisdom to help you find a lower rate. Always double check the T&C of what the competing site offers. Ive seen rates on other sites that include breakfast for cheaper than the stay for breakfast rate marriott.com offers. The best one I recently found, was the competing rate matched the marriott.com non-refundable rate. I figured the competing rate would have the same condition, but it was fully refundable. I got a rate of $64! The lowest I have gotten was for about $52. The FD agent said that was only a few dollars more than their employee rate!

I hope that helps. Its somewhat complex and will take some due diligence to find. You dont need to book 2 reservations though.