Drives stopping all at once in FW 1.3.7

I’ve just realized that the drives in my Drobo v2 are now going to sleep all in the same moment (making a little louder but now single noise while parking their heads) rather than in sequence. The staggered spin-up is still there. Anyone noticed that or is it only my imagination?

I thought they always slept at once

I guess it doesn’t matter, it’s the staggered spinup which is important