And quite a few places over here to Basil who'll push the
discrepancy limit close to the 3% boundary, and they are
smart - if they know the flight and the expected uplift they
will know how much to set on the truck to cheat and when
and when not to do so.
One screwed up once by 100kg requiring me to order a drip
done (refuelling truck was expecting flight AB123 but it was
suddenly changed on the spot to AB456 requiring much less
uplift) and a full investigation was done. Turns out the truck
was zeroed at 130L for 123 whereas 456 would've been 57L.
Truck bloke wasn't told nor could he see the panel change
and expressed surprise when the flow stopped short of what
he expected as the change occurred about a minute after the
refuelling started.