Don't you "想"是包含在价格内的....After you sign contract, you have to talk with builder base on 1) code: You don't take advantage compare with builders. 2) contract and related amendement or any ( written record with signature and date)....anything were not written in you contract , drawings, appendix, amend etc.. You shall clearify them with builder and get clear response from builder via written base.You can not negotiate with builder for something miss base on you "想".