This excerpt taken from the ALL 10-K filed Feb 24, 2005.
Changes in estimates of profitability on interest-sensitive and variable products may have an adverse effect on results through increased amortization of DAC
DAC related to interest-sensitive life, variable life and annuity and investment contracts is amortized in proportion to EGP over the estimated lives of the contracts. Assumptions underlying EGP, including those relating to margins from mortality, investment margin, contract administration, surrender and other contract charges, are updated from time to time in order to reflect actual and expected experience and its potential effect on the valuation of DAC. Updates to these assumptions could result in DAC unlocking, which in turn could adversely affect our operating results and financial condition.