Once issued, an addendum becomes part of the contract documents. Bidders are usually required to acknowledge each one on the bid form. Ignore a material addendum and the bid can be ruled nonresponsive. Late addenda often force last-minute rework, since a single revision can change quantities, pricing assumptions, and scope.
Addenda keep every bidder on equal footing. Rather than answer one contractor's question privately, the owner publishes the clarification to all planholders. When a significant change lands close to the deadline, agencies often extend the bid date, but that is not guaranteed. Treat the original clock as still running unless the addendum says otherwise. Nonlinear tracks new addenda as they post and compares them to the prior documents, so you can see where a change affects your numbers.
