From what I understand the MEC had nothing to do with it except approving it. W/O management went to AA and they worked this out, THEN went to the union.
The magnitude is what surprised me. But they obviously realized the severity of the problem (keeping pilots) and reacted in the best interest of the company. Not a complete fix, of course. That’s virtually impossible in such a complicated and dynamic business. But it certainly will make a difference in the number of pilots jumping ship.