Mine with the stock Sofirn battery made 3100 lumens. I also noticed that it is creeping up. And mine draws 8,5A
I ope Sofirn take a look at the drivers. I told them there are some issues.
turn the switch to the 10A position. 180° from this. And plug the red wire to the empty hole next to 10A position. Put the red probe to tube edge and the black to battery and then turn the flashlight into turbo and read the numbers.
BTW with long wires you will reading low numbers because at over 4-5A the wires act as a resistance in the circuit. So the best way to measure high power flashlights is a clamp meter.
I replaced the original MCPCB of my C8F 21700, with one I had purchased a few months ago from Sofirn on which I put 3x XP-L2 (UU640H) ,
Now I get almost 3300 lumens(@CRI90) , and almost 13A at the tailcap.
If you are interested in measuring amp loads I would recommend a meter like the UNI-T UT210E for about $25-$30. Measuring the amp draw is a good way for people to compare outputs.
Nowadays we have homemade lumen tubes and integrating spheres to measure actual lumens.