Fuel issue

[Warrie]

Hi all, just had a race in Iracing on the Nordschleife, 5 laps.
I pitted after lap 3, let CC decide the extra fuel.

I ran out of fuel with about 3 minutes left, ending the race in 16th instead of 2nd position

I was mostly drafting behind some other guy so I could pass him on the final straight, which made me save fuel.

In CC I have these settings:
- Enable Iracing refuel ON
- base fuel calculations on max fuel consumption OFF (not sure what this is for?)
- additional fuel to add: 1
That additional fuel is for 1 lap extra so on the Nordschleife I should have way more fuel than would have needed.

During a race I'm really too stressed to calculate fuel in my head and I race in VR so I can't use any of those fuel calculation windows.
Any advice to take this fuel stress of my back?