http://www.thecollegesolution.com/answering-a-dads-financial-aid-question/
Scroll down in this article for an explanation of why the asset protection allowance is shrinking. It has to do with a calculation involving the consumer price index and the present value of an annuity.
Basically when inflation and CPI are low, a working person needs less money invested today to yield a supplemental cash flow to social security in the future upon reaching age 65.