That's actually the original from BG2ToB... and yes, the BGT-weidu uses the BG2ToB xp cap... but no, it's not the same as the BG:EE one... as there there are no HLAs...
The Tweaks An -mod can be used to remove the XP cap via component install and that component can be used with already started game.
I have not seen that cap since I registered here, so please forgive