That would be about right and unfortunately the very reason i hate perko switches. Also hence the reason i run the Blue Seas 7650 ACR kit. To me and most people, a perko switch is just a plain pain in the rear! If you forget to switch just once you can screw yourself. An isolator or (preffered) ACR does all that for you and still leaves you the disconnect option and emergency combining. Save yourself the headache and switch!