Messiah, not sure what you mean by totaliser.... I have to add the value on the three gauges visible to me to work out how much fuel is on board.
But, to answer your question, when accepting the load sheet, if it says I am at or below MBRW, I sign and go.
As the LDP will not allow out of limits sheets, one should know at the time the fuel load is checked to be within the required 3%. if too much fuel has been loaded.
If too much fuel, liaise with the POCO and agree to either off load pax or baggage or freight, or burn the excess before take-off. This of course assumes that the over fuelling doesn't put one above MRW.
As for checking fuel amount on the take-off roll ... get real.