Actually, I just double checked and CT is not prestaged the same way colors are. In fact, enabling level pre-staging is bypassed when you issue a setCT/Level, even if you have Level Prestaging enabled. (I have a question out to Mike on a separate thread to confirm if those are intentional or not.) So, right now, you definitely do not need to have the on and the set Color Temp/level commands. If you were using a color here, you would want the on after the setColor.
Update: If you want to know how to prestage CT on bulbs that support it, you have to issue the CT separate from the level, unlike with RGB. See this post for details.
