Looking at CUL leves right now it would appear that for a lot of them (or rather, all of them), the requirements for trade-in items have been increased at some point, from 1 to 3.

According to old guides I used when leveling crafters on an older character, many leves used to require only 1 item (for example: No More Dumpster Diving - Knight's Bread x1) but now requires 3. I distinctly remember it requiring 1 long after the great leve nerf of 2.1 and literally every leve that used to require 1 of an item is affected.

When was this done, and more importantly, why? Was it necessary to make crafting harder to level or do I just not understand something? It appears some non-CUL leves have been nerfed similarly as well.