(1) Except as provided in RCW 23B.13.270, within thirty days of the later of the effective date of the proposed corporate action, or the date the payment demand is received, the corporation shall pay each dissenter who complied with RCW 23B.13.230 the amount the corporation estimates to be the fair value of the shareholder's shares, plus accrued interest.
(2) The payment must be accompanied by:
(a) The corporation's balance sheet as of the end of a fiscal year ending not more than sixteen months before the date of payment, an income statement for that year, a statement of changes in shareholders' equity for that year, and the latest available interim financial statements, if any;
(b) An explanation of how the corporation estimated the fair value of the shares;
(c) An explanation of how the interest was calculated;
(d) A statement of the dissenter's right to demand payment under RCW 23B.13.280; and
(e) A copy of this chapter.