On our previous Automation software we had the option to insert an item either at an exact time, like absolute time function in Myriad, or at an approx. time, in which case it would play the item after the playing item at the time had finished, i.e. schedule for approx. time of xx:15:00 and it would play after the song finished that is playing at the time, and given it did not cut the song as such it sounded great.
Other than top of the hour or specific times when you need an item to start at an exact time I agree this would be good addition for Myriad. We currently do something that works OK by scheduling in Autotrack by estimating based on typical song lengths to schedule infomercials etc. as we don't use the advert manager.
Cheers - Andy