I'm confused. I need a map reduced to run at 6:45. I don't see 6:45. I see 6:30 and 7:00 but not 6:45. What am I doing wrong ?

You're not doing anything wrong, you can only have a start time on the half hours. You could check the time in your getInputData within a few minutes and if's not the time you want return []

probably still running after 15mins. I would check the average time each execution process.