My take is that Brewtan is made of tannic acid/polyphenols (PP) and when added in the presence of proteins/lipids of opposite charge they combine and precipitate but if PP are added and there are no excess proteins/lipids they would cause haze. You might be like me and have excess PP not proteins. Hoppy styles a little too grassy/astringent? In any event, you'll definitely know if it PP when you see the chilled wort after using polyclar. Night and day difference.