At what "stage" of analysis are the sentences there were exactly twelve books on the table. and there were twelve books on the table, no more and no less. recognized as saying the same thing

I believe the answer is: Semantic analysis

Semantic analysis refers to process of relating syntactic structures, from the lower level such as phrases and clauses to the level of writing as a whole.

This type of analysis is usually conducted if you really wanted to understand the full meaning of the writing even to the smallest details.