The phrase "should it off" is not a grammatically correct statement and would never be used; what I believe you are trying to say is "shut it off." There really is no difference between "shut it off" and "turn it off," both phrases mean the same thing and whatever phrase you use is totally up to your personal preference! I hope this has helped :)

"When do we use 'shut it off' instead of 'turn it off'?" Remember to use "do" when you ask about an action.