I almost thought it might need another recalibration, but at the very least I really think you need to get those solar cts replaced if its dropping - that could be jacking up your calibration. One of my first posts here back in December was something similar - it required a replacement ct and they sent me a fresh device just to be sure - but even then there was a bug they had to fix to get the new one reading correctly. See here to see if any of this matches your symptoms: Failing CT or...? - #2 by NJHaley