I've got a category that has a 3 day turnover, but one song got scheduled twice within three hours. How did that happen?
it is related to M1's 'Play Number'. it is helpful to have a clear understanding about what it is and how it is related to your rotations. you can display the Play Number as a column in the category view. Play Number is Not a Spin Count. it is, rather, a way of displaying what is essentially yes/no. Yes is the higher number, No is the lower number.
Yes/Higher Number means: this song has been scheduled in this current pass thru the list. No/Lower Number means: this song has not yet scheduled in this current pass thru the list. it is not really important what the Play Numbers are, only that there are only TWO numbers attached to all the songs within the category. the numbers could be 10-11, or 202-203, or 45-46, etc.
when you have a category sorted in Rank order, the first song with the lower number is the current "top" of the card stack, meaning that will be the first to be scheduled when you begin your next scheduling run.
when every song in a category has the same number, when the final song in the category is scheduled, then M1 begins scheduling from the top of the stack again and adds one more number to each song as it is scheduled.
one of the principles of the M1 design is that you want every song in a category to get the same number of spins as every other song in the category. now, let's say you are scheduling and M1 stops. You do a search and find a song and drop it into the schedule. that increments the play number. If that particular song had been scheduled earlier in the day by M1 itself, your manual scheduling of it will mean that it is now one-play-ahead of all the others. thus it could be the entire category will turnover one full time before this song gets scheduled by M1 again. so, if the song is in a category that has a 2 1/2 day turnover, this song that you manually searched-and-scheduled on a Monday, might not come up again for 4 to 5 days.
on the other hand, say you have scheduled the next three days in advance, now you are doing some editing and you cut a song from a schedule. M1 removes one number from the play count. thus that song will probably be scheduled first thing when you begin the next New log.
if you cut the song three times....when you begin the next new log, that song will try to schedule three times right away as M1 tries to play catch-up, to get it to where all songs have equal number of plays. this is what happened to you. you "cut" the song from an already-saved schedule, it was then one-play-behind everything else in the category. when you ran your next schedule, M1 did a make-good/catch-up and scheduled the song twice in short order. the only rule that came into play was your Artist Separation rule, which made sure there were two hours between the repeat-play.
if you do your editing BEFORE you save a schedule, this won't happen. the Play Number is only updated when you save the schedule the first time.
if you have cut a song from a scheduled list a couple or more times, and are now running a new log and you see the song come up again in the 'selections' list as you schedule, you should Flip it, then the play number is incremented...meaning M1 will not play catch-up and schedule the song an extra time to make up for the past 'cut' that you did.