Parol or extrinsic evidence.

(1) Consistent additional terms, unless the court finds that the record was intended as a complete and exclusive statement of the terms of the agreement; and (2) Course of performance, course of dealing or usage of trade. (b) Terms in a record may be explained by evidence of course of performance, course of dealing or usage of trade without a preliminary determination by the court that the language used is ambiguous. Terms in a record may also be explained from other sources as determined by the court under applicable law.