I have a new SC1200 and I am installing my DS12A's the first few went fine but now I am having issues. When I go to add a new sensor I go through the process mount add batteries press button for 3-4 seconds the led flashes twice and the counsel chimes twice. When I go back to the panel I see that 2 zones have added when I only installed one sensor. If I delete the second zone the sensor is erased and the remaining zone does not respond. I have 10 sensors in my house and I am showing 17 zones. What am I missing?