RegExp Help With Look Ahead Exclude Group

I'm building some regex searches and ran into one I can't seem to solve.  I'm searching for all incorrect capitalization and punctuations of Split "S" (the aircraft maneuver).  The expression I'm using is:

[Ss]plit[ -]“?[Ss]”?(?<!Split “S")

The goal is to find all combinations of initial caps and punctuation (space, hyphen, quoteddbl) and using a look ahead to exclude the correct term.  It works great at finding all the variations, but also finds [Split "S]"...ignoring the right double quote punctuation.  I'm having no luck, so thought I'd turn to the experts.