I forgot to mention, the aspire line does have some unique advanced features like the lockout and panic mode… Those are not features that are included in the generic zwave dimmer device type handler, because most switches don’t have those features.
So if you want to use something more than just on/off/dim, that’s when you might use a custom device type handler for the 9540.
Here’s one, and you’ll see that the community member who contributed it did so because he wanted to use those advanced features:
But if you don’t need those particular features, you shouldn’t need custom code with it.