There might be another way to do it with all 3 of 9 series.
I downloaded this Type9Fuel which seems to have fixed the fuel issue. Problem is I forgot who it belonged too. It only has a IndicFuel.jpg and NSS_Uboat9_CR.sim file to show how to change the fuel comsumption and NSS_Uboat9_CR.sim file for Minitweaker to uses it for configuring
You set the new values from -0.13 to -0.086 and save. I found my traveling distance to be more realistic. I can upload it for you. Assuming I'm right about it fixing fuel issue.:hmm:
Anyhow if someone know what this is pls correct me if I'm wrong.

There was no Readme file to it.
If I'm right and then I can upload it to FF if you want.