(c)  dividing the sum by the aggregate amount of the assumed net reductions in principal balance or notional amount, as applicable, referred to in clause (a). The  information  shown  for  each  Notional  Class  is  for  illustrative  purposes  only,  as  a Notional Class is not entitled to distributions of principal and has no weighted average life. The weighted average life shown for each Notional Class has been calculated on the assumption that a reduction in the Class Notional Balance thereof is a distribution of principal. The Weighted Average Lives are likely to vary, perhaps significantly, from those set forth in the tables below due to the differences between the actual characteristics of   the   Mortgage   Loans   underlying   the   related   Trust   Assets   and   the   Modeling Assumptions. S-18