Joshue Martín de Blas, a long time friend of Hybrid Assistant, has put to good use the Fuel Trim charts of Hybrid Reporter.
In his own words:
These 2 Fuel trims graphics are of the same trip, but with different LPG brand. It's clear that in one case the effective Fuel Trim is bigger (and the fuel consumption higher also), because the ECU needs to make much more corrections tho the injection time.
some more information on fuel trims may be found here: