Obviously, C Dog may mean his statistics as hyperbole, but they are certainly incorrect as written. There are many threads on this topic, and certainly some strong opinions, but it is worth noting that it is not as simply answered as "œno".
Multiple pairs most often may not work out. But they sometimes do, and it may depend on the clown species (ocellaris clowns seem more prone to allow this than many other species) and individual personalities, the presence of certain anemones, and other aspects of the tank, when they are introduced, etc.
That said, the only time I tried it it worked fine long term, and I know if has for others as well.
I had a spawning pair of ocellaris clowns and a spawning pair of pink skunks that were only a few inches apart in a 120. The ocellaris could easily have moved away since they were not even in a host anemone, but rather in a leather. But they chose to stay put and the pairs coexisted for several years, each regularly spawning.