Bill, the persistent long term ones, I really believe are shills for the $$$$$$$$$ fuse companies, as no one can be that ****** for that long, so there’s no outcome if you challenge them to an blind a/b because they will never do it.
Better asking them to get their manufacturer’s of these boutique $150+ fuses to come on here to these pages and back up what the they are saying, especially in regards to AC mains directional fuses.
Cheers George