You are right about the functionality.
Sorry I didn't update my question. I opened it up a few weeks ago and saw that the sucking jet pump was disconnected from the level sending unit (which is just a sensor that sends the gas level of the tank to the computer). The tab on the level sending unit that holds the sucking jet pump connected had experienced fatigue and was too loose to keep the pump on when the car experienced strong vibrations. I connected the sucking jet pump to the level sending unit again, sealed everything up, and started the car. The OBC told me that the small tank was now empty.
I ordered a new unit and popped it in since the sucking jet pump would have fallen off again without a proper tab.
BTW, I think the PN above for the level sending unit is for a vert. My coupe PN from realOEM was different and had a blue top, not orange.