The problem still comes down to the fact that tenses, aspects, persons, etc. are linguistic categories, whereas situations happen in the real world. It's like countable and uncountable nouns: the difference is based on the real world but then language goes its own merry way and gets those of us who have to explain it more and more confused.

One book I did find helpful when I first started wrestling with all this in a teaching context was Michael Lewis's "The English Verb".

Bingley

Bingley