What's wrong with letting the drive(s) wake when there is activity and sleep when there is none? Are you just trying to eliminate the 2 second wait while the drives start up?
I'm guessing this is directed at me, so I'll answer
For me, when the drives spin up, it takes a bit of time 10-20 seconds maybe, and during this time, everything is on HOLD, and nothing will respond. I don't like this.
ALL of my files are on the server. If I start a computer, there's a 90%+ chance that it will want to access a file at some point, so this would be a good indicator to just spin up the drives right away, before I request a file, and prevent the delay above.
When all computers have shut down, there is nothing that will try to access the drive, so it makes sense to use that as an indicator to spin them down right away, vs. waiting 15 or 30 minutes to spin them down.
In the end, not a big deal to spin them down, but I think I can change the script very minimally to accomplish this in addition to the spinning up, so why not?