Mopeka Tank Sensor for Odd Shape Tanks

I have the update but there is no documentation of how to set the level increments. I have guessed a few times but the results are inconsistent. When you create a new level point it has a sensor level% and volume %. I assume volume is the tank level and because I have a 100 gallon tank, any percentage such as 30% would be 30 gallons. It doesn’t appear to work this way. Sensor level is a percentage and I believe it should be a cm value. Does anyone have any input on this as no matter what I enter in on a point does not correspond to what you end up with on the level of the tank. I know my tank levels as I “calibrated” it with lines on the translucent tank and I can visually see any water level. The Mopeka measures in CM and in the Victron Console settings you can edit these values. Can anyone figure out how to calculate this?