Like everyone else has said, those letters are just indications that your standardized test scores are probably within the range where they will actually consider you. But you must also keep in mind that some of these colleges accept less than ten percent of their applicants when eighty to ninety percent have test scores and grades that make them eligible for consideration. I can personally attest that those letters mean absolutely nothing. I got those letters from every single Ivy, Caltech, MIT, Duke, Johns Hopkins, etc., and some of the schools that sent me those letters accepted me, some rejected me, and some waitlisted me. You truly won’t know until you get your admission decisions.