At the carrier I work at, we have the following structure :
- Flight Planner within 'Flight Technical Dispatch' - they 'plan' the actual flight - fuel, weather, weights, routes, ATC clearances etc.
- CLC or 'Centralised Load control' - these are the good folk that perform ALL of the weight and balance functions - trims, provisional loadsheets, final loadsheets and send the final figures to the aircraft via ACARS
- TRM or 'Turnround Manager' - these folk are physically at the aircraft side and work with Passenger Services, Ramp, Baggage, Loading, Crew etc to facilitate a safe environment at the gate and also to send the final figures back to CLC for close-out.
I'm not saying it's perfect, but that's our set-up.