MPC CLOCK-Sync PROBLEM

This thing really make me nuts.
I ve been preapering live performance with MPC2000XL and my other synths,while I ve been workin on my album.Same tracks for the live and album,but tracks for the album will be mixed mastered and more polished.
I ve stared to record song,route everthynig on multiple outs,when I ve recorded everthing and started to do the
arrange I notice that tempo do not match.I did the sync over Logic X,I ve tried with Midi clock,I ve tried with MTC,and every time I ve tried the same thing,on the start of the the first bar on every sequnce(4bars) it does a little delay like 20ms but only at the first bar.Then I ve tried to record without sync,I will put in tempo by myself I thought,this won't be a problem,just put in the grid,then I ve notice that tempo of mpc is little bit oscilating,like it is not constant .I ve checked sample rates on my AD DA but everything match,I ve tried in logic 9,in Ableton always the same thing.I ve checked tempo change option but it OFF...and I m going crazy...I am producer of Electronic music house/techno and in my genre,the constant tempo/bpm is
really important,maybe not for a a live performance but for releasing tracks it s really important.
Is it maybe hardware issue by mpc...
I really would be thankful for any advice...THANK YOU and sorry for my bad english

When the MPC is synced as a slave, it's normal to see the tempo change a bit. As long as it sounds like it's in sync, it shoudn't be a problem.

The problem is your computer not the MPC ... computer clocks are known for their instability when syncing/attempting to sync external midi gear

i had the same problem myself but got one of these to drive my external drum machines/sequencers and now things are super tight and always on the grid.

http://www.s-n-d.com/acme4e_a.html

expensive but worth it