Because the controller just sits idle, that's why.
You move the controller, the data is sent and then sits idle until you do something else. Hence, the 4 banks. The problem is that when you change banks and then change back and have to make a change, then you might have to go through some values you don't want. I don't have this problem, but I'm also highly selective about what I do and don't place under MIDI control to help avoid problems. Since during my events, the only things I really need to deal with live are fogger units, and the rest of the show is more or less on auto pilot, it works.
To each theirr their own.
HTP and LTP are there for users to be able to take manual control over things on an as-needed basis. Otherwise, in auto mode, as you see, it does what is programmed. It's working properly.