There are three versions of the 20-quart Hobart bench top mixer, the A-200, the AS-200 and the AS-200-T The only difference is that the "S" designation is for "stir". and the "T" designation stands for "timed" as this mixer has a timer. The "S" designation mixers have a very slow (half speed) stirring speed that might be useful when making a bowl of cake batter to prevent splash out, or to prevent dusting such as is commonly encountered when a fermented sponge is placed in the bowl followed by the remainder of the flour and dry ingredients. However, Now, I don't know if this is sanctioned by Hobart, but when I'm faced with these issues and all I've got is an A-200 I just quickly flip the switch between on and off, like switching a light switch for a few revolutions and then mix in low (#1) speed until I can go to a higher speed without dusting everything within a 5-foot radius of the mixer. Don't worry about looking for an AS-200, you already have a gem of a mixer.
By the way, a slightly smaller, but equally as good of a mixer is the Hobart A-120/AS-120 mixer. This mixer is just a slightly smaller version of the A-200 having a 12-quart bowl capacity. Reverse spiral hooks are available for this mixer too as are a wide assortment of other mixing agitators, and if your mixer has the optional attachment head, you can buy a "pelican head" attachment for cutting, slicing, etc. Due to the great number of attachments available for these mixers, I have been known to refer to them as the grown man's, or woman's Barbie Doll.
Tom Lehmann/The Dough Doctor