My high school was relatively complicated about how this happened. And, to make matters more interesting, starting in my junior year, class rank and grading scale both changed. Let me explain:
First two years, it worked like this:
Each class was worth a certain amount of credit, equal to the number of class periods per week multiplied by 0.2. Thus, a once-a-day class was 1.0 credit, a science class that included an additional once a week lab period was 1.2 credits, a gym class that was twice a week was 0.4 credits, etc.
Then, each class has a weight of 1.40, 1.30, 1.15 or 1.00 depending on the level of the class: Honors/AP, accelerated, standard, or remedial.
Then, finally, grade:
93-100 -> A -> 4.0
85-92 -> B -> 3.0
77-84 -> C -> 2.0
70-76 -> D -> 1.0
0-69 -> F -> 0.0
Then, weighted GPA is calculated as SumOf(Credit * Weight * GradeValue) / SumOf(Credit)
Still with me? Ok, good.
Before the start of my junior year, there were two major changes. One was how grading happened. Namely, that the 10-point scale was far more common among most districts, and thus our 7-point system was detrimental to college-bound seniors. So, we transitioned to 90-100 = A, 80-89 = B, etc.
Additionally, there was some lobbying by students (which started in particular in one of my history classes at the time), noting that the weighting and grading system was a bit skewed towards encouraging students to enroll in lower level classes than they were otherwise able, in order to ace them,
rather than ever challenging themselves. (Consider that a B in an honors course would be worth essentially 3.0 * 1.40 = 4.20, while an A in even just a standard level course would be worth 4.0 * 1.15 = 4.60.) The result was that gradevalue and weight would be combined in the following way:
For grades of A/B/C/D, Honors/AP would be worth 6/5/4/3, accelerated worth 5/4/3/2, and standard or remedial worth 4/3/2/1.
There were a small handful of students (maybe 10 of us at most) who took literally all honors/AP everything, every possible chance. Not all of us had
straight A's (I did not), but needless to say all finished in the top 10% of the class. The two who did have perfect GPA, tied for valedictorian.
All transcripts that were sent out included some pre-canned notes about the mid-season rule change, too, for whatever that's worth.