There is a huge gap between saying SAT's relate to finishing your freshman year and your GPA. Granted finishing your freshman year depends on GPA, but it's more a question of doing the basics. AKA doing your homework without mommy and daddy there, handing things in on time, not cheating, going to class and those activity's are far more independent of HS GPA than parents want to admit.
On the other hand GPA's over 3 depend a lot on how hard your classes are, how heavy the work load, if you have a full/part time job which are less dependent on the student's innate qualities.
On the other hand GPA's over 3 depend a lot on how hard your classes are, how heavy the work load, if you have a full/part time job which are less dependent on the student's innate qualities.