Maybe I am wrong here, but it seems to me that the Add-on switches are not supposed to have an effect on the base switch; that it is superimposed on the base switch.
But here, when I use an Add-on on top of “Natural, Note Length == Very Short”
it destroys the “Very Short” condition and reverts the Base Switch to “Natural”:
With the Add-on:
This seems like a mistake to me.