Assigned Altitude problems

[Airbrakes 0]

Every flight now I'm getting a problem with the assigned altitude by ATC. For example, my cruise altitude is FL370 and crossing the TA, my altimeters are set to standard pressure. However ATC still thinks I'm above/below FL370 even though my instruments say otherwise and they keep reminding me. One more thing to note, this only happens with the PMDG744. I end up canceling the IFR flight plan and closing the program. This is obviously very annoying.System specs:WinXP 64 BitFSXRC vs 4.3Active Sky AdvancedPMDG 744FThanks in advanced.

[Airbrakes 0]

Never mind, I found the culprit.I had pressure smoothing control from FSUIPC turned on so I turned it off. :(