Auto cut-off is only a safety device to avoid spillage. At times just the fumes of the fuel may activate the trigger to shut down the flow to avoid spillage. You can always shake the vehicle a little and continue from where the fuel flow stopped. I don't think it has anything to do with your FE calculations, unless I have misunderstood your problem.
For diesel vehicles no matter how much you shake the vehicle there is still a possibility of few air pockets. For perfect calculation, I suggest you fill your tank doing all these antics. Drive the car for atleast 2 Kms after your initial topup. You will be surprised to see it taking in another couple of litres. Now note down this reading. After having run the vehicle till your next fill, repeat the same process and note down the reading at your second topup. Its cumbersome alright but you can't get better perfection than this.
My vehicle has a capacity of 60 litres. I run the car for about 300 kms each time and topup with about 30-35 litres every time. This gives me a fairly accurate picture of my cars condition. I have afuel chart, which gives me the entire history of the vehicle since it was purchased ( 3 years back) |