If the related Mortgage Loans prepay at rates that are generally above the Effective Range for any PAC or TAC Class, its supporting Classes may be retired earlier than that PAC  or TAC Class, and its Weighted Average Life may be shortened, perhaps significantly. Assumability Each Mortgage Loan may be assumed, subject to HUD review and approval, upon the sale of the related Mortgaged Property. See "Yield, Maturity and Prepayment Considerations – Assumability of Government Loans" in the Base Offering Circular. Final Distribution Date The Final Distribution Date for each Class, which is set forth on the front cover of this Supplement  or  on  Schedule  I  to  this  Supplement,  is  the  latest  date  on  which  the  related Class Principal Balance or Class Notional Balance will be reduced to zero. •   The actual retirement of any Class may occur earlier than its Final Distribution Date. •   According to the terms of the Ginnie Mae Guaranty, Ginnie Mae will guarantee payment in full of the Class Principal Balance of each Class of Securities no later than its Final Distribution Date. Modeling Assumptions The tables that follow have been prepared on the basis of the following assumptions (the "Modeling Assumptions"), among others: 1.  The Mortgage Loans underlying the Trust Assets have the assumed characteristics shown under "Assumed Characteristics of the Mortgage Loans Underlying the Trust Assets" in the Terms  Sheet,  except  in  the  case  of  information  set  forth  under  the  0%  PSA  Prepayment Assumption Rate, for which each Mortgage Loan is assumed to have an original and a remaining term to maturity of 360 months and a Mortgage Rate of 1.50% per annum higher than the related Certificate Rate. 2.  The  Mortgage  Loans  prepay  at  the  constant  percentages  of  PSA  (described  below) shown in the related table. 3.  Distributions  on  the  Securities  are  always  received  on  the  20th  day  of  the  month, whether or not a Business Day, commencing in August 2007. 4.  A termination of the Trust does not occur. 5.  The Closing Date for the Securities is July 30, 2007. 6.  No expenses or fees are paid by the Trust other than the Trustee Fee. 7.  Each Class is held from the Closing Date and is not exchanged in whole or in part. When  reading  the  tables  and  the  related  text,  investors  should  bear  in  mind  that  the Modeling Assumptions, like any other stated assumptions, are unlikely to be entirely consistent with actual experience. •   For example, most of the Mortgage Loans will not have the characteristics assumed, many Distribution Dates will occur on a Business Day after the 20th of the month, and the Trustee may cause a termination of the Trust as described under "Description of the Securities – Termination" in this Supplement. S-16