@andrewkm

 

I've sent this off to the tab list developer.

 

Omg this thread is right... I thought I had 50,044 xp but only had 49,916 after renaming an item and combining mending to a rod on anvil

 

I can add my findings on this. Every time you use exp for repairing enchanting or anything beides exchanging stars the xp messes up my tab meter has been far over 15k exp Wrong somehow

 

For reliable results, use /exp command.
It looks like the developer of the tab plugin is not willing to fix this.