Class B-4 Optimal Principal Amount As to any Distribution Date, an amount equal to the sum of (I) the sum, as to each Outstanding Mortgage Loan, of the product of (x) the Non-PO Fraction with respect to such Mortgage Loan and (y) the sum of:
Class B-5 Optimal Principal Amount As to any Distribution Date, an amount equal to the sum of (I) the sum, as to each Outstanding Mortgage Loan, of the product of (x) the Non-PO Fraction with respect to such Mortgage Loan and (y) the sum of:
Class B-2 Optimal Principal Amount As to any Distribution Date, an amount equal to the sum of (I) the sum, as to each Outstanding Mortgage Loan, of the product of (x) the Non-PO Fraction with respect to such Mortgage Loan and (y) the sum of:
Class B-3 Optimal Principal Amount As to any Distribution Date, an amount equal to the sum of (I) the sum, as to each Outstanding Mortgage Loan, of the product of (x) the Non-PO Fraction with respect to such Mortgage Loan and (y) the sum of:
Class B-1 Optimal Principal Amount As to any Distribution Date, an amount equal to the sum of (I) the sum, as to each Outstanding Mortgage Loan, of the product of (x) the Non-PO Fraction with respect to such Mortgage Loan and (y) the sum of: