When you get a big drop like you did last night at +2 it is a good idea to test again at say+4 to make sure theBG is not going to drop too low. Then you need to make a judgement call as to whether you need to test again depending on how much lower the BG has dropped and how close to nadir Owen is.
It doesn’t have to be +6 in the am cycle. It can be anywhere from+4 to +7. That should catch the nadir.