The
DDP is per night, so yes, you will have 6 of each. The credits start the day you arrive and are good until midnight the day you check out. One of the ways we were able to "stretch" our CS credits (so we could eat breakfast the last day) was to share a few meals throughout the week.
There are some CS places where a lunch was big enough for me and my 10 year old to share. On check out day, the kids were able to eat a full breakfast. DH and I don't eat big in the AM (and he doesn't like to eat much when we fly) so it worked out great!
This year, we are doing the QSDP, and will be paying OOP our last night for a sit down meal, so that will leave us a CS for the last day.
Good luck!