The Q400 can be... Touchy for W&B. The plane is naturally nose heavy. On a full load it rarely matters, however if we're at something like 50-60% that's where the issues begin.
The Q cabin is broken down to 4 cabin zones A through D. Section A are the 3 rows of preferred seats, so the W&B system will do whatever it can to not move people out of here.
The most common move the system requests is B to D. Generally we need people in each pair of seats aft of row 15, but will be dependent on cargo load.
Also if you see us doing what looks like a passenger count, even if the flight is full, we're giving the pilots the number of Male, Female and Children per section, to cover the Balance, and see if any cargo/bags need to be moved to the forward baggage hold.
When checking in, RES will attempt to do a rough W&B pass to minimize the number of moves we need to do onboard.