Timing

Could I possibly get a simple run down on how timing works on the EOS family.

There is Intensity up/down, F C B and Duration. I understand Duration is a total of things happening in the cue and it does not necessarily mean a total of all the times in all the columns. What I don't understand is how I can have a cue with Int, C and B (no F time) each set at 3 but the Duration is 6 or 9. I just did a show where there were many repeated cues. All I was using were conventionals, two spot movers and 6 LED movers. When some of the cues would run they would complete in the 3 seconds I set upon initial record but others would complete the visual in 3 seconds then keep running an additional 3 or 9 seconds with nothing visible.

Also when I set an intensity delay for the LED's on a cue to keep them from suddenly popping on at 1% becasue they really don't fade 0-100, that cue and the cue above them would attach a + symbol and run an additional whatever seconds depending on what the intensity delay was set for in the next cue. Why would additional timing be added to the cue before?

I can attach the show file if it would help.

I'm sure it's something simple but I can't figure it out and hitting About doesn't help.