I agree, its amazing stuff... plus I'm pretty sure I went overboard with the volume of this stuff that I'm using.. so hopefully and decline in effectiveness is negligible.
But I did ask them to explain this.. they said that the pellets crack apart.. so when probed further I got from them that most of this degradation is that the pellets break apart, becoming small enough to leave the filter bag. They also said the loss of the round surface is the other contributor to the loss.
So far I'm not seeing any issue of anything leaving my pillow case/filter bag. So it's probably finer than 100 micron, which would explain my difficulty flushing it clean then too. But hopefully the tradeoff will be that less of these pieces will leave the bag.