If it works the same way as last year it would be 50% off of the dining for both adults and kids. Then there is also a room savings on top of that. I hate to commit to any calculations because as I've said in other posts I don't have enough data yet to do the analysis but I will next week. If my assumptions are right for a family of 4 with 2 Disney adults and 2 Disney kids the SPD COULD POSSIBLY be a better deal than a 15% off Room if your room rate is in the $600 per night or less range. HOWEVER the variables from there would be how many nights, weekday vs. weekend nights, how much do you spend to eat each day vs. the dining plan expense, tips on table service meals (if you wouldn't have eaten as many table service meals without the dining plan), etc. etc.