On my 2021, I figure the percentages shown on the first screen are proportional to the timers. They do not indicate how full of water or air the bags actually are. The software is supposed to learn after 5 drain/fills and automatically adjust the timers from that point on to get closer to your actual required drain/fill times and thus making the percentages shown more accurate.

I don’t know all of this for certain. Anyone feel free to correct me. There are other factors as well; bags not venting well, bags folded over and not filling symmetrically, software version, etc.

I have never seen a ballast sensor fault. Where does it show up and how is it indicated?