InFlightFuel is now available in the ipad app store. I’ve been using it as my main tool for fuel management. The tank gauges on the Cirrus are notoriously inaccurate, but the totalizer is pretty good. It watches fuel burn over time and simply adds up the results. As long as you update InFlightFuel when you switch tanks, it works out great.
In truth, I’m sorta bummed that this app was needed. Isn’t this something that should be part of Garmin Perspective? It sure would by a lot more convenient if it were actually hooked up to the tank switch so that you didn’t have to update a separate app. I do remember the Avidyne system in the Piper Archer I used to fly had this functionality built in.