Cost blowouts.
Volume builders win the quote with a low number. Then variations start. Cheap substitutions, hidden contingencies, corners cut on quality. By the time you see the real cost, you're locked in and the build is already compromised.
Open-book pricing.
You see every invoice. Trade selection is a conversation. Every change agreed before it happens. From quote to handover the numbers stay visible, so what you pay matches what was built.