I have seen more than a few errors in transferring figures from the loadsheet into the FMS. After the first time, I made it a habit to 'hang around' until I could see the FMS calculate the TOW and that it confirmed what my loadsheet showed.
Working for an LHR handling agent, I spent 3 years on the SQ contract. While the SQ crews showed some of the most professional attitude and abilities of all the airlines I handled, they were not infallible. Yet I am still a bit surprised at the group loss of SA here.
In my expereince, errors occurred most often when using manual load and trim sheets as opposed to system generated ones, since the former were infrequently used and the layout would sometimes cause the pilots to use the maximum figures for ZFW and TOW rather than the actuals. While the usual cross checks would catch 'some' typical errors, the pilots would just have to rely on the ability of the load controller to get it right regarding many others, such as ZFW and CG calcs. Whether manual or system generated, they are only as accurate as the figures that are being inserted. The fact that many pilots didn't know their way around manual load and trim sheets too well always concerned me, but not as much as the declining standards of ground ops and load controllers. The relavent lack of experience and lowering training standards of the latter combined with occasional flight crew errors is just an accident waiting to happen IMO.
The error that should have been spotted first by the FO and subsequently by the Captain seems to have occurred due to bad SA and lack of familiarity with the aircraft type and its typical weights. I would urge that pre-departure procedures are changed to allow the load controller to confirm that 'his' figures are faithfully transferred into the FMS and that the loadsheet is only signed when the ATOW on the loadsheet is cross-checked and confirmed by the FMS.
Centralised load planning and loadsheet generation is another aspect that IMO increases the possibility of such errors going undetected before they reach an unsuspecting flight crew.
We had the ultimate blame culture at BMHS and Aviance, which used disciplinary measures to deal with such errors, even when lack of training and too many flights in a given period were obviously the cause. This just forced people to cover up errors and worst of all, to let them go in the hope that nobody would notice. I agree with the sentiments implied abocve, that humans are prone to human errors. I would add that improving procedures that ensure errors such as these have more chance of being spotted by increasing the number of layers that they must pass through.