I had a very hard time to type myself I considered almost any logical and Fi-Ego type. Fortunately I am now sure that I am a SLI also thanks to this book from Reinin (http://www.the16types.info/vbulletin...-Reinin-s-Book). Reinin doesnt use exactly the Model A but a similar system. By Reinin is correlated with deep introspection so in my opinion should make it easier to determine your Sociotype. That's how Reinin describes as leading function of the ILI and as problem area of the SLI.
When I am looking in the forum for people who struggle(d) to find their type @William and @Destroypuppy come to my mind both selftype themself as Sociotypes with weak . Of course I am aware that this small samplesize is not enough to proof my thesis in a stochastics way anyway what are your thoughts is weak correlated with problems in self-typing?