After having just recently started the game, I made my first pie yesterday. What I noticed with the making of the pie was I take an empty bucket, hit a cow in the head with it and he gives me milk. When I make the pie, however, my bucket of milk doesn't turn back into an empty bucket, instead it simply vanishes, like I got distracted and instead of pouring the milk out, I just shoved it into the rest of my pie filling and slapped that culinary masterpiece into the oven.
It was the same thing when making paper, crushing my water, bucket and all between the 2 planks and flax fibres.
The milk bucket disappearing I can agree with, because sometimes the residue from milk directly from the belly of a cow can be a bit hard to get out of a wooden container, but it honestly seems to me like the water recipe at least would go empty bucket>water bucket>empty bucket.
I'm not sure how this would make it fit into the pricing formula that you have been working with, unless there was some way to make it ignore the "cost" of the liquid element somehow.
An alternate suggestion to this, if it was possible to ignore the bucket cost, would be to put in a bucket upgrade. A steel bucket, perhaps, that would be reusable, even if the wooden bucket stayed as-is.
Another suggestion that I have in the crafting realm is Wrought Iron Fencing. Not much, but basically, iron versions of the current wooden ones that would add more variety and uniqueness to the individual homesteads.
Edited for horrible typos