Lowest hypos don't have a number. I've had a fair amount of low BS over the years. A real hypo is where you wake up , touch your face, see your hand covered in blood and go back sleep. Wake up again, was it a dream? Check hand, nope not a dream, hand covered in dry blood. Get out of bed, where is the duvet? Go toilet, look in mirror, realise top of nose is slightly detached from rest of head along with some strange facial marks and a split lip. Find duvet at bottom of staircase along with pillow. Make a call to sister to say " think I've had an hypo " this is followed by a trip to A&E to have bridge of nose put back in place with stitches ( stitches without anaesthetic OUCH!!!! ) . To this day I have no idea of what happened that day. But it was a hypo.
I have more tales to tell but I could never give you a BS reading.