Meghan, definitely do a little number crunching when the deals come out. In the past, deluxe hotels have received standard
disney dining plan on the free dining deal. This is 75.49/night for each individual over 10y/o and 25.75/night for each child under 10. So for your family, if this deal remains, would be a savings of 226.47 (2 adults and 1 Disney Adult 12y/o) + 77.25 (3 disney kids under 10 y/o) = $303.75/night savings * number of nights you're staying at Disney World. Keep in mind some additional costs that Disney may try to throw at you. Last year, you had to stay a certain number of nights and you had to have park hopper to have free dining. So, if the minimum is 5 nights, but you're only staying 4, this might not be the deal for you. Or, if you're not doing park hopper and have to add that expense to 6 tickets, that might not be ideal for you. Park Hopper is about $65 +/- additional expense on every person. However, this is a one time charge, so if staying 7 nights, you'd save $2,126.25 on the DDP, but have to then add back in the one time cost of -$390 ($65 per person) for the park hopper for a total savings of $1,736.25. One additional factor, do you think you'll eat this much food if still staying CL? We usually either get the DP or CL, but not both.
To figure the deluxe club level discount, I'd figure your currently booked rack rate less taxes and then multiply by the % of the discount on mousesaver's historical data (Google Mousesavers Disney World Historical Discounts). Again, these might change, but they can give you a good idea of a discount to use for estimations. With resort only discounts, you may need to be flexible with room category as well as resort hotel. Example: In September, it's fairly common for some deluxe resorts to be discounted 25-30%, but some resorts are excluded completely or have a reduced discount. Example, Polynesian is very popular so it may be discounted only 15%. If you're currently set to stay CL at Polynesian, would you be willing to move to Contemporary or Boardwalk Inn to save 30%? Or perhaps they exclude club level altogether this time (not likely but for illustration purposes), are you willing to stay at a different category to get the discount? Or maybe not, so you go with the free dining promotion above that doesn't usually have as many categories excluded, if any. At Boardwalk the second week of September, Standard Club Level Rack Rate is $651.71. *If* they do 30% off on this category at BWI, that would be a savings of $195.51/night * number of nights you're staying at Disney World.
So to conclude, in this hypothetical, it would probably make more sense for you to take advantage of the Free Standard Dining ($303.75/night savings) vs 30% Club Level at BWI ($195.51/night savings), especially if you were doing park hopper tickets already and staying more than 5 nights already. Further as I mentioned above, if you do the dining plan, it might not be worth staying CL for all the additional free food, so you might get even more savings by downgrading your room category.