So at the local kitchen studio (in the House of Crafts, you can tell right away^^) they were not at all uptight. When I asked for the price of X or Y the third or fourth time, he gave me his catalog, told me what margin he added on it, and that way I could figure out piece by piece whether this or that was worth the extra cost for me or not.
If your local kitchen builders are not so open, you can certainly use the IKEA price changes as a guideline. It's always about the same thing, the extra effort and the material need to be paid for.