[Zz] Refine hopper limit to "open" hoppers

I've heard there is a limit of 20 hoppers per chunk. But according to this source https://community.gophersvids.com/topic ... -solution/ , hoppers do not cause significant lag if they are covered with an inventory item. How about refining the rule to only allow 20 hoppers to be actively looking for entity items to suck down, rather than limiting the total number of hoppers?