Security Group 3 PSA Prepayment Assumption Rates Class EB Class YD Distribution Date 0% 75% 150% 250% 400% 0% 75% 150% 250% 400% Initial Percent ..................     100 100 100 100 100 100 100 100 100 100 May 2005  ..........................    100 100 98 92 84 100 100 100 100 100 May 2006  ..........................    100 100 94 79 27 100 100 100 100 100 May 2007  ..........................    100 100 90 56 1 100 100 100 100 39 May 2008  ..........................    100 100 88 33 0 100 100 100 100 0 May 2009  ..........................    100 100 85 17 0 100 100 100 100 0 May 2010  ..........................    100 100 84 7 0 100 100 100 100 0 May 2011  ..........................    100 100 83 1 0 100 100 100 78 0 May 2012  ..........................    100 100 82 0 0 100 100 100 26 0 May 2013  ..........................    100 100 81 0 0 100 100 100 15 0 May 2014  ..........................    100 100 79 0 0 100 100 100 12 0 May 2015  ..........................    100 100 76 0 0 100 100 100 10 0 May 2016  ..........................    100 100 73 0 0 100 100 99 8 0 May 2017  ..........................    100 100 69 0 0 100 100 62 7 0 May 2018  ..........................    100 100 64 0 0 100 100 25 6 0 May 2019  ..........................    100 100 58 0 0 100 100 0 5 0 May 2020  ..........................    100 98 52 0 0 100 100 0 4 0 May 2021  ..........................    100 95 46 0 0 100 100 0 3 0 May 2022  ..........................    100 89 41 0 0 100 0 0 2 0 May 2023  ..........................    100 86 36 0 0 100 0 0 2 0 May 2024  ..........................    100 82 31 0 0 100 0 0 2 0 May 2025  ..........................    100 77 26 0 0 100 0 0 1 0 May 2026  ..........................    100 70 22 0 0 100 0 0 1 0 May 2027  ..........................    100 62 18 0 0 100 0 0 1 0 May 2028  ..........................    100 51 14 0 0 100 0 0 1 0 May 2029  .......................... 94 40 11 0 0 100 0 0 0 0 May 2030  .......................... 83 30 8 0 0 0 0 0 0 0 May 2031  .......................... 66 19 5 0 0 0 0 0 0 0 May 2032  .......................... 33 9 2 0 0 0 0 0 0 0 May 2033  .......................... 0 0 0 0 0 0 0 0 0 0 May 2034  .......................... 0 0 0 0 0 0 0 0 0 0 Weighted Average Life (years)  ..................    27.3 23.6 15.7 3.4 1.6 25.6 17.5 13.3 8.4 3.0 Security Group 4 PSA Prepayment Assumption Rates Class IY Distribution Date 0% 75% 150% 250% 400% Initial Percent ..................     100 100 100 100 100 May 2005  ..........................    100 99 99 98 97 May 2006  .......................... 99 98 97 95 93 May 2007  .......................... 99 94 68 65 33 May 2008  .......................... 99 58 25 22 1 May 2009  .......................... 98 24 6 2 0 May 2010  .......................... 98 8 4 1 0 May 2011  .......................... 97 7 3 0 0 May 2012  .......................... 92 6 2 0 0 May 2013  .......................... 77 5 1 0 0 May 2014  .......................... 60 4 0 0 0 May 2015  .......................... 43 3 0 0 0 May 2016  .......................... 25 2 0 0 0 May 2017  .......................... 8 1 0 0 0 May 2018  .......................... 7 1 0 0 0 May 2019  .......................... 7 0 0 0 0 May 2020  .......................... 6 0 0 0 0 May 2021  .......................... 5 0 0 0 0 May 2022  .......................... 4 0 0 0 0 May 2023  .......................... 3 0 0 0 0 May 2024  .......................... 2 0 0 0 0 May 2025  .......................... 1 0 0 0 0 May 2026  .......................... 0 0 0 0 0 May 2027  .......................... 0 0 0 0 0 May 2028  .......................... 0 0 0 0 0 May 2029  .......................... 0 0 0 0 0 May 2030  .......................... 0 0 0 0 0 May 2031  .......................... 0 0 0 0 0 May 2032  .......................... 0 0 0 0 0 May 2033  .......................... 0 0 0 0 0 May 2034  .......................... 0 0 0 0 0 Weighted Average Life (years)  ..................    10.8 4.6 3.5 3.3 2.8 S-28