I see nothing wrong with the sgt's example. There's a difference between "when" and "each time," but the difference involves quantity, not function. In this situation, both phrases would work the same way. In other words, "Each time you play a tale" on a tale is the same as "When you play this" at the moment they are played.
I get what you're saying though. I went through the same thinking process when it first happened for me on Gemp. I won't speak for you, but I was trying to apply MTG constructs to LotR, which rarely works.