I’ve just read Rebecca Ellis’ March column, “What is Substantial Completion” as well as the similar discussion toward the front of the magazine. We used to run into similar issues and finally realized the only way to tackle the issue is through contract terms established prior to starting the construction so that everyone knows what the rules will be when we get to the finish line.
If there is nothing in a contract and everyone is relying on “beneficial occupancy” or even using standard AIA contract language that “Substantial Completion is the stage in the progress of the Work when the Work, or designated portion thereof that the Owner agrees to accept separately, is sufficiently complete in accordance with the Contract Documents so the Owner can occupy or utilize the Work for its intended use,” expect a fight and unhappiness. In either case, there always will be an argument with the owner wanting more and the contractor wanting less to reach this legal point (that generally would be tied to liquidated or other completion damages).