18.(1) If there is any doubt or dispute as to the existence or amount of any debt, the Board shall decide whether the debts exists and determine its amount: Provided that a decree of a Civil Court relating to a debt shall be conclusive evidence as to the existence and amount of the debt as between the parties to the decree. (2) Before passing any order under sections 19, 21 or 22 the Board, after considering the statements of debt submitted under section 11 and sub-section (1) of section 13 and the evidence produced, if any, after having given an opportunity to the parties to appear and be heard shall, in accordance with rules made under this Act, determine in respect of each debt the amount of the principal and the amount of the arrears of interest due thereon from the debtor up to the date of such determination. (3) [Omitted by section 10 of the Bengal Agricultural Debtors (Amendment) Act, 1940 (Act No. VIII of 1940).] (4) When the Board has determined under sub-section (2) the amounts of the principal of a debt due from a debtor and of the arrears of interest due thereon, the decision of the Board in this respect shall not be questioned in any Civil Court or in any manner other than that provided in this Act. (5) Notwithstanding anything contained in this Act or in any other law for the time being in force or in any contract, where a creditor has taken possession on any terms whatsoever of any immovable property of the debtor as security for, or in lieu of payment of, any portion of the principal of the debt or any portion of the interest thereon, and where the Court has not pronounced a final decree for foreclosure or has not conformed a sale held in execution of a final decree for the sale of the property, the Board shall, in making the determination under sub-section (2), prepare an account in the prescribed manner of the receipts of the creditor derived from the said property and after deducting the expenses properly incurred by the creditor (of which an account shall similarly be prepared) either for the cultivation or for the management of the said property, shall credit the sum of such receipts in reduction of the amount, if any, from time to time due to the creditor as interest on the original principal of the debt and, so far as such sum exceeds any interest due, in reduction or discharge, as the case may be, of such original principal. (6) In determining under this section the amount of arrears of interest due- (a) the rate of interest taken shall not, notwithstanding anything contained in any contract, exceed the rate recoverable in a suit or other proceedings for the recovery of the interest under any law for the time being in force, and (b) where the debt relates to a loan in kind or where there is any stipulation for the payment of interest in kind, the money value of the principal or interest shall, where the circumstances require such calculation, be calculated in the manner prescribed.