I am having a terrible time with my Samsung induction / convection range (model # NEH9970WS). The oven temperature is very inconsistent. It heats up fine but then can't seem to maintain anywhere close to a consistent temperature after that. It sometimes drops more than 70F before trying to reheat. I've done some reading and checked the resistance on the convection heating element. I am getting between 45 and 50 Ohms. I read online it should be 70 Ohms. Is this correct...should it be 70 Ohms? Is it time for a new heating element?