1. It points directly towards its high potential for failure.
2. It addresses the fact that it is running through the same motions -- repeatedly -- as a conceit of the film.
3. It cleverly integrates both 1 & 2 (basic tenets of metafiction) seamlessly into the dialogue while maintaining the illusion of the fourth wall.
4. The elements that are altered work to confuse the characters exactly because they aren't identical (and the characters are otherwise not good policemen).
5. Those small changes then become a repeated source of comedy.
6. And finally, the actors actually seem to enjoy what they're doing.