11 M.R.S. §2-1202: Final expression; parol or extrinsic evidence

Terms with respect to which the confirmatory memoranda of the parties agree or that are otherwise set forth in a record intended by the parties as a final expression of their agreement with respect to such terms as are included therein may not be contradicted by evidence of any prior agreement or of a contemporaneous oral agreement but may be explained or supplemented:

(1). By course of dealing or usage of trade or by course of performance; and

(2). By evidence of consistent additional terms unless the court finds the record to have been intended also as a complete and exclusive statement of the terms of the agreement.