[Freesurfer] true-Talairach vs mni-Talairach?

Dear Freesurfers,

I am a little bit confused about the talairach coordinates in Freesurfer. I have two diffrent versions of Freesurfer: 4.0.1 and 4.0.5. I opend brain.mgz in tkmedit and try to do the following things: when I type in Freesurfer 4.0.1 in the tkmedit-window some Talairach coordinates, the numbers I typed change a bit. I think it is because tkmedit think that I gave mni-Talairach an modified them to true-talairach. Is this right? When I type the same in Freesurfer 4.0.5 the talairach-numbers I type in the window stay the same. So, can I be sure that Freesurfer 4.0.5 knows that I type the true-talairach(?), and show me the correct true-talairach-point in brain.mgz ? Thanks for your answers!