Additional costs for oak stair covering instead of beech – usury?

I am aware that there is a difference between usury as it is commonly understood and usury in the legal sense.

Of course, you can see the difference between beech wood and oak because the grain alone is simply different. Also the base color tone, no staining can help with that. We have oiled everything in oak, and the tiles look like that too.

Yes, and I no longer want a beech staircase, not just because of the appearance, the wood is much softer and more susceptible to dents, scratches, and such.

We had also considered having it done later. However, now the staircase builder actually called again and lo and behold, there are no extra material costs but the costs for the entire staircase, meaning the costs for the staircase will then be credited to us by the general contractor. I don’t yet know what to make of that, but this will probably work out better. Let’s see what comes of it in the end. But that the staircase builder didn’t tell us that this morning when we asked three times would have saved us some gray hairs.

However, the stair builder actually called again now and lo and behold, these are not additional material costs but the costs for the entire staircase,

The stair builder called this afternoon? Saturday afternoon? Well, that's what I call service :)

I wonder if you can even tell whether it is beech or oak when he gives you a color guarantee.

Besides the color, there is also the grain and texture.

Such a change could be arranged directly with the handyman without going through the general contractor. That should turn out to be somewhat more attractive. The contract with the general contractor remains the same, only the wood is different. We had that with some individual details, not the staircase, and it was satisfactory. Best regards Gabriele

Yes, and I no longer want a beech staircase not just because of the look, the wood is much softer and more prone to dents, scratches, and the like.

I agree with you about the grain and color - you can't compare that.
However, hardness is not an argument here. Beech and oak are specified with exactly the same hardness!