The panning is wrong because they recorded the classic soundtrack from the MT-32 and if you're playing the game files raw from the MT-32 (outside the game) the panning is reversed. They obviously based the SE soundtrack mix on their classic recordings which is why the SE soundtrack is also wrong. In their zeal to get it as faithful to the original as possible they made a bunch of rookie mistakes and it made the whole project suffer drastically.
"Booyah! Look out, LeChuck! Here comes Guybrush Threepwood's glowing sword of hot monkey vengeance!"
-Guybrush Threepwood, Tales of Monkey Island