I loose my air in about 8 hours. Which is fine with me, because compressed air left in the system for long periods will cause condensation anyway. I dump the air (I have front & back air bags) before I set the hydraulic levelers as well. My low air goes off at 60 psi and I have never even come close to that. Your low air buzzer setting seems to be kinda high at 100 psi, I would think you could hit that at certain situations as you found.
Bill
2003 28' Show Hauler Motorhome on a 1995 FL 120
www.showhauler.com