In Berg v. Hudesman, 115 Wn.2d 657, 801 P.2d 222 (1990), the Court rejected the "plain meaning rule" in favor of the "context rule." As an aid in ascertaining the intent of contracting parties, a court may admit extrinsic evidence relating to the entire set of circumstances under which the contract was formed, including the subsequent conduct of the contracting parties and the reasonableness of the parties' respective interpretations. Berg, 115 Wn.2d at 667.