I have a construction contract that specifies allowances for various items, I.E. $2,500 for light fixtures. After the construction the builder now says that he includes his "profit" in that allowance. In effect taking the actual cost of the fixtures that we picked out ($2,400) and adding 13% so that we owe him $212 instead of getting $100 back. This was not a cost plus job. Is this standard practice? He has done it with all the allowances, but did not state it in the contract as such.