ERJ 175 Captain reported incorrect MEL maintenance write up for vibration resulted in return to gate and refused aircraft.

Narrative

On taxi out we got a LP VIB on one of our engines. There was already a maintenance write up about an LP high VIB with an MEL that covered HP VIB. I believe that on the corrective action they did a run up and verified the VIB was erratic and I think a sensor issue. I called maintenance control to verify and I was told that the MEL was for HP VIB only and that it looked like they had put the incorrect MEL. I wrote up the LP VIB that was very erratic and going from a 4.1 to a 2.1 and to different numbers constantly. I also put that the MEL was for HP only and not LP. We returned to gate and got into another aircraft to do our flight. On the original write up they wrote LP high VIB and not sure if there was some confusion with maintenance and they took it as HP instead of LP. Not sure what happened the day it was written up and if maintenance was in a hurry or just missed that detail about LP vs HP and got confused and entered the wrong MEL. Not rushing and having somebody else be there to back you up on the write up; which I believe MX usually does; can help to not make mistakes.