Mark, ours turned out to be a defective meter...
Sometime before we purchased her the DC amp meter and heat sink was hit by a surge; lightening, short, something. It fried the heat sink and when we puchased her the surveyor pointed it out to me. At first I thought it was the same thing as you; a defective appliance on one of the circuits. When I turned on our running lights it would jump to 30 amps, or when the water pump came on it would jump to 20 amps.It could be a short, as you suspect, but also check your meter carefully. I had to remove it completely before I noticed the damaged heat sink. If you have access to a hand held amp meter check to see if the two are in synch.TerryP.S. Paneltronics made many of the power panels for Hunter boats. I contacted them, sent the defective one to them and they sent me an identical replacement for about $25. Let us know what you find out.