The totalizer would work great on some flights, but under count on others.
If you keep half an eye on the systems, you should spot that.
The way one normally works is that you level off in cruise, set up the engine etc, and look at the appropriate GPS page to see the computed FOB at the loaded destination. On most flights, this figure changes suprisingly little through the flight. Tailwind improves it of course, and headwind degrades it. But the nearer you are to destination, the less difference the wind makes, obviously.
If you have a sticky transducer, which is possible but is extremely unlikely to be thoroughly sticky on some flights and perfectly OK on others, you will see wild fluctuations in the computed LFOB (landing fuel on board) figure. Not to mention wild fluctuations in the current flow rate indicated on both the flow instrument and the GPS page.
Some notes
here and
here 