Is the C of G issue because of too much of a forward or an aft trim, or both scenarios?
If so, this maybe the case of a full Business class load in the front (and maybe cargo), and too few Y pax down the back, or vice versa...
Hardly anyone has checked bags anymore in Business so one cannot offset out of trim situations with the hold baggage.
We had a particular problem with Transavia Holland on a 737-200 used for the LGW-AMS scheduled services, which had a movable business cabin so you never knew much in advance of the variable loads - It was a pig to trim which for a 737-200 was unusual, but caused by a lot of extra metal installed in the front area due to some re-skinning (post Aloha HNL)