This has been an extremely interesting thread for me since I am just finishing up installing a Maretron FFM-100 Fuel Management system. I won't go in to the cost ($$$$$) but below are the data that I expect to see. The FFM-100 displays its data on a DSM -150 that is completely programable. Once the sensors are installed in the fuel lines (2 for each engine) and the sensor are in each fuel tank, the system is automatic. No calibration required after the set up.
In the past I've had 2 FloScans and try as I did, I could never get them close to what I was seeing at the pump.
Panbo: The Marine Electronics Hub: Maretron FFM100 fuel flow monitor test (part 1), as good as it gets?