purps - as a test, can you do the following,
In the web admin:
Advanced > Configuration > events > create advanced event
Type whatever you want in the description, select Media Player > Watching media, or Listening to media, for audio or video respectively.
create, you'll see the event in the list, select Criteria
select Create new segment
next to event parameter, Select FK_Room
Select the appropriate room.
Then save. The criteria is now defined.
click on Edit Event Commands
under Device, find your App Server, that is the child of your media director, and select it.
Then use the Set Volume command
In the volume device data, put in a number. click save.
Play something, see if your volume value sticks.