Add each flight, then copy the summary at the bottom into your email to OPS.
The aircraft list and weights are locked. Enter the fleet code once on this iPad and it stays unlocked, even with no signal.
This updates as you go. Flights are kept on this iPad until you clear them. Payload is the lower of MTOW − FOW − takeoff fuel and MZFW − FOW. Takeoff fuel is start fuel ÷ 2.205 (rounded up) less 45 kg taxi; payload is rounded down. Check against your load sheet.