Original Message

They seem worse in Airbus products than any other brand...

The EC130 was horribly inaccurate (the % bar is technically what you're supposed to use and there's a supplemental fuel chart for what your actual gallons are because the indicator on the VMD is always wrong).  

The EC145 was consistently off and required you to be in similar flight profile when taking first and second reading to compare.  I agree about seeing the 20 minutes it sits full and then starts moving like the EC135 comment above.  

OH-58/UH-1/OH-6 didn't have lots of tick marks to see exactly where you were at but they were always very accurate.  

UH-60 probably the most accurate.  Would guess the AH-64 and CH-47 were similar.  Bigger airframes using pricier capacitance fuel probes is probably why.