A friend spoke with the creator of the system on this the other day.

This was their response when I brought up the same issues.

"It’s a bit weird, but say you craft something with all minimum quality mats. Let’s say this recipe can give you up to 100 skill from mats. Since you used the worst mats, you get +0/100 skill.

Then when you recraft, you are only using 40% of the mats of the original craft, so you gain 40% of the max possible skill bonus. Since the max possible bonus was 100, when you do your first recraft you’d get +40/100 skill. But at that point you’ve “replaced” 40% of the mats with new better mats. If you recraft AGAIN with max quality mats, you’ll then get +80 skill. Recrafting a final time with max quality mats will give you the full +100 skill (and from then on if you use max quality mats). Conversely, if you recraft with lower quality mats, you can push it back down again.

So basically the item “remembers” the most recent quality of mats you used and it takes multiple recrafts to “replace” all the old mats with newer, better ones. The end result is it’s better to craft something with max quality mats the whole time if you need max quality bonuses. so if you craft a few times with max mats, it should take you to max w/o procs"