Why is Bob's name called four times in Project Mayhem?

In Project Mayhem there are no rules, no names, no questions. But there are rules in fact.

Everything Tyler says is fact. He said, "There are no names in Project Mayhem". After that he says (we see him as the Narrator) "His name was Robert Paulsen".

The members of P. M. are confused with this paradox, and trying to build in their "religion" or "mindset". They see this as a kind of revelation, and see this as a rule-like something.

EDIT

The 4 times has no importance, they just keep it repeating to try to understand and give a significant abstract meaning for that. They follow Tyler as a messiah, take care all of his words.

Tyler Durden (Brad Pitt) was the person who invented Project Mayhem. Tyler was the person who says there are no names in Project Mayhem.

The Narrator (Edward Norton) is not aware at this point that he is also Tyler Durden. He's not (consciously) of the same mindset. When Bob dies, he still has the human element of wanting to ensure Bob's life (and death) has meaning, so he reminds the members of PM that Bob has a name. He is a person.

The members of PM become confused, because (from what they know) Tyler Durden is first telling them that PM members have no name, and then that Bob does, in fact, have a name. These guys are trained to be drones, so they basically regurgitate whatever they're told. They chant "His name is Robert Paulsen" believing Tyler wants them to acknowledge Bob, and that PM members receive names when they die.

If I'm not mistaken, they actually chant this many times over, and not just 4 times.