I think the wording of it was strange to begin with, which has caused a lot of confusion. I had to read it a few times before I got it. Think of it this way:
Use the mod as in previous years. If you have a few shots in which it just doesn't work (an extreme closeup of a face, for example) or if you happen to forget to put it into a shot, don't sweat it. However check out the shots in which you didn't include it. They must not add up to more than 15 seconds. If your shot includes the mod element at some point in it's duration, even if it's not in frame the whole time, that's fine, and you don't need to count that towards the 15 seconds.