Weaver's Smock

I have this smock, but when I use "Clothcraft: Restorer's Touch" I do not see anything happen. Am I doing something wrong/How do I use this thing?

My understanding is that this is an improved, "Repair Furnace" option.

Repair Furnace is 6 light fewell to repair durability by X amount.
Restorer's Touch is 10 light fewell to repair durability by Y amount.

Y being stronger than X. Only at synergy 55 so far, so I haven't bothered while I've been skilling up since I don't care when the furnace gets to 0 durability.

You may have to spam it a few times to see the durability increase.

I've only used the ability a few times but from what I see it's pretty lackluster, at least comparatively to the cooking one.

Do you have to have "Repair Furnace" leveled in addition to the Smock? or are they independent?