negative mortgage amortization?

check this and see

http://www.mortgagefit.com/negative-amortization.html

the purpose has been to reduce the mortgage during the month. In other words if you have an interest only loan you are paying off the interest, but not the balance. This mortgage tip of paying off the interest works only if you can t afford to make a larger payment or are using the loan for an investment.

the major purpose of negative amortization has been to reduce the mortgage payment at the beginning of the loan contract. It has been used for this purpose on both fixed-rate mortgages and adjustable rate mortgages. A second purpose, applicable only to ARMs, has been to reduce the potential for payment shock -- a very large increase in the mortgage payment associated with an increase in the ARM interest rate.

For reducing mortgage payment at begining the negative amortization has been used. The downside of negative amortization is that the payment must be increased later in the life of the mortgage. The larger the amount of negative amortization and the longer the period over which it occurs, the larger the increase in the payment that will be needed later on to fully amortize the loan.