Performance data usually includes the runway takeoff data, that tell the pilot's which RWY's they can use during prevailing weather conditions and how to set the trim/flaps and other stuff accordingly. In changing or inclement weather conditions this can be a challenge.

UA's system has been automated for years, and occasionally this happens to them too. IIRC, the gate agent and the ramp have to have final numbers (they call it their "lockout") confirmed within 5 minutes of push or so to calculate CG and TO weights for the FMS. If it is outside of limits, it alerts the load planner and dispatcher who can take the appropriate actions.