At CX we uplink the Takeoff data from the main frame in HK. We then enter it whilst carefully crosschecking the load sheet in a SET routine patter.
However, it is still possible to screw up the data entry and have both guys miss it.
We are only human after all.
The ONLY way is for the aircraft to weigh itself and come up with V1 VR and V2 numbers which if more than a few knots out wont let you enter the numbers from the RTOW calculations without giving you a clear warning message first.
Until this happens, no matter which way your company does it, there is no way to take out the "human error" aspect.
Just be slow and methodical, know you aircraft and what to expect.