I now believe the drive is entering the 'Standby' state - it was not obvious by observing the provided illumination LEDs on the outside of the unit. I just couldn't detect a noticeable difference between the full illumination vs. 20% illumination the document describes. Poor design, or just yet another indication of my fading faculties. But I was able to feel the drive cease spinning so it does seem to be going into Standby even if the LEDs are glowing.
I'll PM you my paypal address for my $20