Automatic xcheck and warning
Answer to the problem = An automated Xcheck. We cannot go back to the RTOW paper charts so why not make the best usage of automation.
The computer system used, either a cockpit BLT/LPC/OIS or that used via ACARS needs to have a sub routine working in the back ground. This routine should know the usual average TOW for the airlines sectors (a simple summation program) and if there is a significant variation to that on the day then display a warning screen. This would advise the crew of a possible error, to recalculate their TOW again and reinsert/send the revalidated data (ZFW, TO Fuel, etc).