A Dual Apper is a borrower who submits applications through two loan providers, usually mortgage brokers, without their knowledge.  

Borrowers sometimes submit more than one loan application as a way of protecting themselves against the hazards inherent in committing to one loan provider before the price is locked.  Mortgage rate locking does not provide complete protection, because the lock price does not finalize the settlement costs other than the points. At this point, the settlement costs are merely “estimates”.

The alternative to dual apping that protects you better, is a fair mortgage broker that let’s you know the estimated costs before the process begins. While the price of the mortgage cannot be set in advance, the mortgage broker fees can.