8640 is the number of rooms at value resorts
6102 is the number of rooms at deluxe resorts
There are certain deluxe resorts that fill up SUPER fast....those are typically the Polynesian, Wilderness Lodge, The Epcot Area Resorts and the Animal Kingdom Lodge.
I've stayed at the Polynesian the past 2 Augusts and let me tell you it was PACKED! The other thing you should take into account is that more people take advantage of 40% off codes or AP rates to book deluxes. The mentality is typically "if im saving 40% i might as well stay deluxe."
Another thing to take into account is the baby boomers. My parents were born in the 50s and are therefore part of the boom. They have been taking me to WDW since I was 2. We started off-property. Then went mod (as no values existed) then went deluxe, and now we often get 2 rooms deluxe. If you asked us 5 or 7 years ago if we'd ever be a "deluxe family" we would have flat out laughed. Demographics play a huge part.
Values are typically aimed at young families, where deluxes are aimed more at adults with teens or adult children. In addition, multiple visit guests begin to want to explore different resorts. First timers with young kids are prone to gravitate to the more "disney themed" hotels.
For all these reasons,
Free Dining is in fact used to fill up the values in what would usually be a very slow season. Disney wants young families there at the end of Aug and beginning of Sept so must offer a big draw for them to take their kids out of school.