Surcharge for beech staircase compared to oak staircase

seems high to me as well.
in my inquiries, I had rather 500 - 2000 Euro surcharge for oak instead of beech.
are you sure this is only about the material? Has the structure not changed?
how large is the order overall?
maybe you still have a lot of wood elsewhere on the staircase.

The order totals about 340K plus incidental construction costs. We only requested the change to oak. That means, in my opinion, the staircase itself should remain the same as in the offer.
It concerns 2 staircases (staircase from ground floor to attic and staircase from ground floor to basement). I do not yet know the number of steps.
But I already sense that something might not be right, or rather, that I should request a precise and detailed justification for the price difference.

ok, so it is at least one more staircase than I have. insofar, it is still high, but not completely offensive. if the staircase overall requires a lot of material (long gallery?), then that can be the case. I would still ask if it can be excluded from the scope of services. parts can be subcontracted to third parties with relatively little risk.

Thank you very much for the information and support

The material price for oak is significantly higher than for beech. For example, looking at Holzland, the price per square meter for beech stair tread panels is € 68.75, while for oak it is € 185.16 per square meter.

so kostet bei Treppenstufenplatten der Quadratmeter Buche € 68,75, während für den Quadratmeter Eiche € 185,16 zu zahlen sind.

So that is an extra €120 for 4 steps. For €5,100 that would be 170 steps that could be upgraded for the OP. So from the basement to the 12th floor.

For us, it would have been a surcharge of 1400 euros from beech to oak per staircase (14 or 15 steps). Times 3, so 4200 euros. Billed directly through the staircase manufacturer. Others who also built with this one took the beech standard in unfinished and stained and clear lacquered it themselves. Looks cool too!