Can someone help me find the answers to some questions concerning pay while being on TDRL?

I am trying to figure out my pay while being on TDRL. My orders sending me to TDRL stated my longevity pay is 50% but my disability is 70% and I should get paid the higher. DFAS insists I should get paid 50% and just say its regulation. Who is right? Is there anyone who got the higher of the two, or am I just smoking crack?