"Precise, not just formal" would be fair in this case.

(The reason I say "in this case" is that reaching for precision is a very different mental strategy than reaching for formality. Many reach for formality who have no concept of how to reach for precision, and end up sticking tags on their black boxes and putting the tags into a logic. So you don't create a logical framework as your first step in reaching for precision; your first step is to figure out what your black boxes are, and then think about your strategy for looking inside...)