For the current to increase you need to increase the voltage, current = voltage/resistance and the resistance of the MAF is going to be a constant so the voltage has to increase to increase the current. They could do this but I would not have thought so but will read up to see.
My fuel economy varies considerably, if I am driving it and not towing I get between 11 & 12 l/100km. the wife usually drives it to and from work which is only 5km from home and she gets around 15l/100km. Have tried to teach her how to drive properly to get better economy but that did not end well.