Now I have no clue what you need. The 6 is the length of the interval when dose is above 15 (>15), the unit is 'hour', if you need more accuracy, you can easily switch it to 'minutes'. 6 hours is between first time point when dose>15, which is 07JUN2017:21:56:00, to the last time point where dose > 15, which is 08JUN2017:03:14:00.
" it should be 07JUN2017:21:56:00 - 07JUN2017:19:39:00"? This is when the dose is not above 15, you did not mention you need that as well, but that can be easily done.
The thing is, there is a conflict between your description and your wanted outcome (this part is confusing).
... View more