I have a craft with an interior which utilizes lots of MFDs. When testing, I noticed that no matter what I do, the MFD I have displaying fuel levels will display 0% Monopropellant and 0% battery, even though both have a pathway to the control chip that I am using and I made sure that each part between the battery and monopropellant tanks and the control chip all have fuel line enabled.
i don't think the feul lines are nessisary but if they are idk