black and white pages + a softcover in colour = prize doubled?

Hey,

I wanted to print a book (trade) with 241 – 260 pages in black and white, with a softcover in colour.

Of course with  "Black and White printing" the cover would be in black and white, so I changed it to "Colour printing" and the prize changed from 9,95 € to 26,95 €. I think the prize is so high, because this option is for photo books, so all pages would be in colours. Is their an option for just the cover or would I really have to pay nearly three times as much just for a cover with colours?