One of those Mini-Baskets (the one with lots of holes) is for the Spotscrubber machine.The more significant difference is that one fits on either a Straight-8 or a Straight-4 and the Spotscrubber one fits over the Spiral.
The FS dispenser is the later variety that works (it doesn't hold on to a portion of the softener that it releases during the final spin).
I wish one of those very rare powdered detergent dispensers would show up somewhere but they were only available for like maybe two years.