The parts

There are only four things to understand.

Draw Fee

Two percent of each trade. It cannot charge to hold or to send. Consequence: a Carrier always knows the take.

Edge Schedule

A published map from Pass Count to Edge Share, written at construction. It cannot be reset. Consequence: an older floor hones more of every trade than a young one.

Pass Count

The cumulative count of settlements. Every transfer reads it. It cannot fall. Consequence: the Edge Share never falls with it.

Honed WHET

Units removed from issue by the Edge Share. They cannot be reissued. Consequence: the issue only ever shrinks when the Trade Floor is used.