Captiva diesel reflashing

I HAVE not been too impressed with the fuel consumption of my Holden Captiva diesel, though I am impressed with the rest of the package. I contacted my dealer with the ``reflashing'' option and was told this was a recalibration of the readout and would not alter the actual litres per 100km. They contended it was a faulty computer rather than high consumption. My 2008 Commodore will return 9 litres/100km on a trip to Sydney, but the best I can get out of the Captiva is 10 litres and with our fuel prices the vehicle choice is obvious.