By use I mean, how to apply it when typing? How tangible is the method? Knowing that each type has two egos doesn't really help, there has to be a strategy on how to spot how it manifests. Your model, as well thought out as it is, is useless when you can't take it to figure out something in an effective and realistic way.
You can apply it the same way as Model A. Model D will actually make typing easier, since you now know that LIE sometimes looks like LSI. You will also be able to distinguish between clearly extroverted LIEs and ambiverted LIEs.
If the LIE is in an introverted environment then the "LSI-ness" is noticeable, just like my "ENFp-ness" is noticeable in an extroverted environment.