Here's how Author Sort displays with the KOBOTOUCH plugin enabled (KOBOTOUCHEXTENDED plugin disabled). It looks like the sort works correctly and as expected.
Just my own visual personal preference - I like/prefer the rendering of the .kepub sort better, where it's displayed as:
Title (Italics)
Series - Number (Index) (All Caps)
Author (Regular Font)
Although, I don't like the 3 different font styles in the example above
