Alright, when I toggled the infinite ore setting off in 5Dim settings it behave as expected. I did another test again now and I think I've been a little confused as well.
It appears that there might have been a issue at first regarding the fuel/power thing which don't seem to happen anymore (not sure what mod caused that) but with the infinite ore enabled in 5Dim it says 12/s with 5000 and 250/s with 100000 I think that is as expected after all when the resource is infinite
It seems like I have wasted your time regarding this issue now, and I'm deeply sorry for that.
I will keep trying to figure out what caused issue with the fuel requirement and let you know if I find out what caused it.