In an action about a consumer transaction, parol or extrinsic evidence of an express warranty is admissible even if it adds to, varies or contradicts the written contract (not where the goods or services were meant for business use), so promises made by sales staff bind the supplier regardless of entire-agreement clauses. Where any part of the transaction is evidenced by a document the supplier provided and a provision is ambiguous, it is interpreted against the supplier. Suppliers should control what is promised at the point of sale and draft documents in plain, unambiguous terms.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.