This is an interesting non-scientific experiment. I have two newly installed toilets, a Toto Ultramax and a Kohler San Rafael. The Kohler unit is in our main bathroom where we have a cat litter box with flushable litter. It does a good job on standard waste, but typically it takes up to 4 flushes and vigorous usage of a toilet brush to flush down all of the kitty litter placed in the Kohler toilet. I thought it would be interesting to see how the Toto would compare in a similar application. One flush got rid of more then 99% of the litter. Slight “touch-up” with a brush and the next flush removed the few remaining grains. That was very impressive. I am certainly glad I listened to the recommendations on this forum for the Ultramax. Why did I get the Kohler? It was a free replacement for an old pressure assisted unit that broke down, so the price was right.