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<p>Perhaps at your school, but not unusual at all. The course grade is typically the sum of all points earned over a semester/quarter. The top xx% earn A’s…</p>
<p>Thus, it doesn’t matter if a Prof gives 4 tests @ 100 points each or four tests @ 65 points each. The top xx still earn A’s. Or perhaps the tests are 65 points each and the final is 130 points (2 times a midterm). Still it does not matter. What matters to the OP is the mean and SD. If the mean is a 75, the result is likely a ~B (or B+ depending on the Prof’s final curve). OTOH, if the mean is a 50, and the SD is 20, then a 75 is an A, since it would be in the top ~16% of all grades. Note, that four students scoring 64 also does not matter since the vast majority of the class did much worse.</p>