Frank, only a retired person with time to spare keeps a fuel record. don't forget if your speedo is say 10% optimistic, your trip recorder will be also, which means you haven't covered as many miles as you thought...
There I go again, the old 'ASS of U & ME' syndrome.
Your right about retired, Easter and I used to be in Management so it was 'Spreadsheets' for breakfast. You've not seen the useless stuff jamming up my laptop.
However, I am distraught now. All those years of false allowances for 10% more miles than covered (ie Grahams little mileage book) and excess tax I must have paid for those overstated 'benefits'.
Ah but if & when I sell a car I should now be allowed to 'clock it' (dock it) by 10% now.