During some tests I ran across a design limitation:
you can have ACP inheritance but just one down the line, while it would have been beneficial for us to have base policies for specific customers and then create a device ACP based on "multiple" inheritance from different base ACPs.
as it is now you are strictly tied global (generic for all devices) -> device specific ACP.
I haven't tried with latest versions but I am pretty sure it didn't change, let me know in case :)