On the FRAM, the carboard end caps may onlyhold it together, but they do colapse. Also, on the one I cut open the carboard is not quite centered, so the metal/rubber valve piece does not seal agaist the cardboard, but part of the corrugated sleeve.
The other thing we are probably running into here is the same as in oils: Companies have different standards in different countries. although a Brazillian Fram is as bad as an American one. I've seen major oil brands that have the same name on products in different countries, one country's being SJ/CH-4, and he other SH/CF-4. Another brand had SH/CG-4 in one country, CF-4 in another, and SF/CD in another. All with the same name.