Additional Work
Having a shell of a room is not what you are after. Projects in San Diego are, many times, bid on a cost plus basis. Any increases in materials and labor reflected in the marketplace add to the cost of the project. Additional work orders implemented after the initial agreement increase the costs as well. Adding 10% to a contractors bid will help prevent shortages requiring cutbacks and provide flexibility for upgrades as you see fit.
Below are some additional links to helpful information