mtc reader offset? mpc and pro tools tempos slightly off

hi, okay I've scrolled through a number of threads but haven't found the answer to my problem. Hope someone can help. I have my mpc2500 and pro tools linked fine. but for a few particular songs i did in reason a while back I wanted to do new drums. i've bussed the audio out of reason and into new pro tools sessions--the synth sounds or whatever no drums. now i'm trying to do the drums in the mpc but the tempos are not matching. 80 in the mpc seems slightly off from 80 in pro tools. the click tracks of pro tools and the mpc are a half step off. i know that there is a time code reader offset option in pro tools. is there a definite known offset sample number between the mpc 2500 and pro tools le7 that I can plug in there to ensure 80 in the mpc is 80 in pro tools? anything else someone would recommend? I just want to make sure the drums won't be off when I track them out into pro tools at the end. the mpc is the master for making the beat but then I switch to pro tools being the master when I track the drums in to make sure everything is on the one. man, i hope this wasn't too confusing. i'm sure i could have said it better. THanks, though.

Chrystal

Trying lowering the H/W buffer setting to the lowest setting in the Playback Engine under the Options menu!