Into the replacement cost one would also factor in the age of the replaced sheets. If they were near the end of their life, the property wouldn't get the full price of new sheets. (Even though I wouldn't be really surprised if it was legal in the US to include a clause that demands multiple amounts of restitution.)

In addition, I would have expected to be given a chance to obtain the complete set of soiled sheets as they would still have value for me.

It also hasn't been established whether the hotel made any attempt to clean the sheets -- apparently not if the timing of the charge is any indication.

I'm not convinced the hotel has a good standing to ask for an amount this high.

HTB.