I find it curious that you recommend changing the diaper twice a week. Just what volume of GPH going through the diaper is this recommendation based on? Do you think a 20 gallon mini-reef should get the same twice a week change as a 500 gallon mega-reef?
I am not sure what they base their recommendations on but BRS did a video on this exact thing and changing your filter sock twice a week was the ideal result.
It isn’t how much stuff is trapped in the material so much as what is in there starts to break down and add the unwanted nutrients into the tank after a few days.
I think this is the video: