I agree mo and normally do 1 and 2 hours and occasionally when I can't quite understand link yesterday. 1 hour @ 7.7, did some exercise (30 mins) 4.4 @ 1.5 hours, 7.5 @ 2 hours!!, 4.8 @ 3 (and all I did was sit at the computer typing)
Talk about bouncing up and down
PS often test after exercise if my fingers and hands have gone numb/cold as this is my indicator for low levels