To allow support of external Macros (like CM15A's Macros) correctly, you need to be able to set up two devices for each house/unit code. One for the 'on' macro and one for the 'off' macro. Currently, the X10 App tries to be fancy, and will not allow you to create a second device.
Let me add, this is closely related to another Wish List item here,
Seperate Off / On Button For example, let's say I have an A5 'on' macro that turns 'on' the front door light and the front foyer light, and later turns them both 'off' 10 minutes later. I also have a separate A5 'off' macro that turns 'on' the side door light and the side mudroom light, and later turns them both 'off' 10 minutes later.
In the X10 App/CM100, I need to be able to create two devices. An A5 'on' device, and an A5 'off' device. Plus, for the first, I need to be able to do multiple on's in a row, with never doing an off. For the second, I need to be able to do multiple off's in a row, with never doing an on.