In a short sale the bank does not care how much extra $$$ you paid.
There is always a gimmick out there. Many have heard that one should pay extra $$$ to pay off their mortgages quicker. The problem is if you end up in a difficult situation through not fault of your own then and you start facing pre-foreclosure and a short sale issues and the bank does not care how much extra $$$ you paid on your mortgage in the past.
Because of the economy of the recent, years I feel it is a good idea that any extra funds you have, to put it into a separate account just in case something happens.
For example, for 5 years you put an extra payment aside in a separate account then you would have five months payment plus interest.
In year six your employer reduces your hours, or you have have to take time off because you or a family member is ill, or worse you loose your job. Then you will have 5 months payments already set aside to assist you through the difficult period.
If you are able to get to save more monthly payments then when you get closer to the end of your mortgage you can just make a lump sum payment and clear the balance in full. That way you always have some kind of a cushion when it comes to your mortgage payments.
Unlike the bi-weekly payment it is not rigid and a third party is not involved in your finances. This is something you can do on your own and increments of your choosing. If one month you only have an extra $5.00 then so be it, but in another month you have an extra $500.00 then so be it.
You see my issue with paying ahead, when you are going through a difficult time the bank does not care how much extra $$$ you paid in the past, they just want the payment/s that is/are due.