Modifying Drobo 5N Disk Drive Spindown time

In the Drobo Online User Guide 2.5, it says that the Disk Drive Spindown time can be modified by going to Drobo Settings>General Settings, at which point an 8-increment slider that allows adjustment from “15 mins” to “Never” should appear.

Following this steps in Dashboard 2.5.3, I only get a checkbox to toggle Disk Drive Spindown on or off without any incremental slider.

How can I adjust the Spindown time?

which guide are you referring to?

I dont think you can modify the spindown time on the 4 and 5 bay units

that can only be adjusted in the 8 and 12 bay units