we run our commercials at 10 after and 40 after the hour...   the only way we have gotten around this it to make a scheduled playlist for each of these times and put in commercials at these times. 

We need to make a interval play list to play them at a certain time each hour.

This brings me to the TOP OF THE HOUR playlist as well
this needs to be able to be played at the TOP of the hour and just not every 60 mins.   doing so every 60 mins says its to be played once per hour which can be played any time during the hour at a 60 min interval.