I was a loadmaster on c 130's a long long time ago! The cg becomes more critical as the weight approaches the max takeoff weight. The permissable cg range becomes less probebly because of the limitations of the control surfaces to move that weight. also.it is not unusual to take off at a weight that is too high to land at because the stresses of landing are higher than takeoff so you have to dump fuel b 4 landing, not a happy thing to have to do if your having a problem in the first place!
On large full size planes we use simplified moments;the true number of moments divided by 1000 so 50 people that weigh 20 lbs more than you thought don't really have that much effect.
Fuel and cargo have the most effect .you cannot move the fuel and there are weight limitations
on the deck that varies thru the cargo compartment.
As the weight goes up due mostly to fuel the cg moves foward so I suspect that commuter plane wanted people to move to the rear until he had burned off some fuel.. On that small a plane the weight of the people had more effect. I am a beginner in rc so I apologise for the lecture. Also,my info is dated(I'm old). I'm sure there is more accurate info available. Just trying to help in an area I have some limited knowledge. CAZ