You can email the TiW office and ask them: WDW.Tables.In.Wonderland@disney.com
Or Call them at (407) 566-5858 (Monday – Friday, 9:00 a.m. – 5:00 p.m. EST)
I have stopped eating at restaurants that can afford to take the pitiful DDP reimbursement, but can't give the small TIW discount.
I figure those of us who pay cash are already subsidizing the DDP so I just decided that if they could not afford that discount I didn't have to overpay to subsidize DDP