Securities that Receive Principal on the Basis of Schedules As described in this Supplement, each PAC and TAC Class will receive principal payments in accordance with a schedule calculated on the basis of, among other things, a Structuring Range or Rate. See "Terms Sheet – Scheduled Principal Balances." However, whether any such Class will adhere to its schedule and receive "Scheduled Payments" on a Distribution Date will largely depend on the level of prepayments experienced by the related Mortgage Loans. Each PAC and TAC Class exhibits an Effective Range or Rate of constant prepayment rates at which such Class will receive Scheduled Payments. That range or rate  may differ from the Structuring Range or Rate used to create the related principal balance schedule. Based on the Modeling Assumptions, the initial Effective Ranges or Rate for the PAC and TAC Classes are as follows: Initial Effective Ranges PAC Classes DA, DB, DC, DE, DG, HA and HB (in the aggregate)........................................................ 125% PSA through 300% PSA YA  ........................................................................................ 180% PSA through 288% PSA EP, PA and PB (in the aggregate)................................ 99% PSA through 250% PSA JA, JB and JC (in the aggregate) .................................. 120% PSA through 200% PSA WA and WZ (in the aggregate) .................................... 325% PSA through 600% PSA EN and NB (in the aggregate)...................................... 275% PSA through 530% PSA Initial Effective Rate TAC Class ZN ........................................................................................ 530% PSA •  The principal payment stability of the PAC Classes will be supported by the related TAC and Support Classes. •  The principal payment stability of the TAC Class will be supported by the related Support Classes. If all of the Classes supporting a given Class are retired before the Class being supported is retired, the outstanding Class will no longer have an Effective Range or Rate and will become more sensitive to prepayments on the related Mortgage Loans. There is no assurance that the related Mortgage Loans will have the characteristics assumed in the Modeling Assumptions, which were used to determine the initial Effective Ranges or Rate. If the initial Effective Ranges or Rate  were calculated using the actual characteristics of the related Mortgage Loans, the initial Effective Ranges or Rate could differ from those shown in the above tables or an initial Effective Rate might not exist. Therefore, even if the Mortgage Loans  were  to  prepay  at  a  constant  rate  within  the  initial  Effective  Range  or  at  the  initial Effective Rate shown for any Class in the above tables, that Class could fail to receive Scheduled Payments. Moreover, the Mortgage Loans will not prepay at any constant rate. Non-constant prepay- ment  rates  can  cause  any  PAC  or  TAC  Class  not  to  receive  Scheduled  Payments,  even  if prepayment rates remain within the initial Effective Range (or if prepayment rates average the Effective Rate), if any, for that Class. Further, the Effective Range for any PAC Class can narrow or  shift  over  time  and  the  Effective  Rate  for  any  TAC  Class  can  change  or  cease  to  exist depending on the actual characteristics of the related Mortgage Loans. S-21