That sounds just fine tbh, ive fitted a new sender/fan sensor and full rewire and mine sticks on the gauge at O, then my fans cut in just before the N when in traffic etc and it bumps down past O on the gauge then cuts out.

I know what you mean with tha paranoid issue mate , im on edge just before my fans cut in waiting for the tamp to go down lol , thats why I got a switch in the cab for the fans just incase.