This is something that is available for a nominal fee. It is designed for customers who expect to pay down their principle balance a lot in the first 5 years of servicing
The #1 Lender in the country offers this. They will retain servicing for 5 years so if the customer wishes to make some large principle payments they will recast your loan free of charge. This is much better than just sending a principle payment or paying the closing costs of a refinance.