I dont see the option for missing values. Probably because it is not a "time of day" type column. As in i have a column that goes from 1 - 300. (and not a standard 60 min an hour type of thing)
Essentially the data point of minute where the event doesnt occur, does not exist. The data is like this.
1 - 20
4 - 6
9 - 15
Sorry for the late reply. Did you ever figure this out? If not, could you attach a packaged workbook. If the data is too sensitive, could you mock up a fake data set instead and recreate your problem.