Got an analysis for my 2.5T from oil analyzers... aaaand 5% fuel in 3350 miles.. ouch! (nailbyt)
The oil happened to be a cheap Castrol GTX magnatec. If I understand correctly, it should not affect fuel levels? Better oil should have just maintained the viscosity better.
Possibly more relevant fact was that I ran only 87 gas this time, as a low interval experiment

Switching to 91 and AmsoilOE, will check again in 3500.
At the same time got a report for a q5 with 70+k miles. Only 1.6% over 9500 miles. Most of the mileage was rough due to carbon buildup.