You'll only need ADR's for table service or character meals. Itjust depends on what meal you want your table service to be used at. Your table service credit is not specifically for dinner, but you do get more for you money by doing so.
I would suggest eating earlier or later than usual, that will give you a greater chance of getting ADRs. For example, if you're thinking of going to Boma for dinner, instead of 6pm, plan on 8pm or 4:30pm.
Let us know how you do.