No one can answer this question for your MOCs. The large majority of LOAs do get appointments. Does it mean these candidates have an advantage during the Nom process.? None of us know, as each MOC evaluates things differently. A candidate gets an LOA because they have an impressive record. A strong application speaks for itself and is the main advantage to a candidate during the Nom process. Remember someone with an LOA only needs a Nom, so they can be 10 of 10 on a slate and that gets them their Nom. This is something you can't control. Do well on your interview and amaze the board, it's the part you have control over.