I was once told of a similar situation in a high school: AP classes were worth 6.0 in your GPA, while regular ones were worth 4.0. The valedictorian wound up being the person who realized this, took as many AP classes as possible, and as few regular classes as possible.
It is massively stupid and unfair -- but there is a part of me that sees that as preparation for real life, a great deal of which is run in stupid and unfair ways. While you'd like to change that, you also have to know how to respond to it when you can't change it.
The opposite happened when I went through high school. AP classes gave you a .75 bonus to your GPA, Honors classes gave a .5 bonus.
However, many of the AP classes were hard, to the point that the AP exam was laughable. The average grade in AP Biology was a C+, and more than 85% of the class got 5s on the exam. Same thing with calculus, physics, chemistry...
The valedictorian took AP Psychology, Statistics, Environmental Science, and US History, and then went down to the easiest Honors classes he could take. Just a .25 penalty on his GPA bonus... but he was getting 100s in the classes.
The kids who were looking for the hard classes to learn had much lower GPAs.
I am a high school senior taking two college math courses, but to discourage this practice (which costs the school money) the school counts my grade as a 4.0 max in my GPA (AP classes are 5.0, regular are 4.0).
Why is it unfair? The AP courses are more challenging, and therefore get more weight. Isn't the valedictorian (theoretically) the smartest kid in the school?
I enjoyed band so I took it and they didn't have an honors or AP version. So for me to maximize my GPA would mean that I would have to forgo band all four years of my high school existence in order to min-max for GPA.
You are minimizing anything that hurts your GPA. If the highest grade you could get in a course is a 4.0 for a regular course and say a 5.0 for AP or Honors and band is a regular course you wouldn't want to take the hit from band.
If you have all your graduation requirements fulfilled, the system penalizes you for taking any further classes. You improve your GPA by taking a quarter of Nothing/Study Hall if you can't get another AP class.
And indeed, I believe the valedictorian did exactly that, for exactly that reason.
That is indeed exactly what happened -- the valedictorian was in all of the same advanced/AP classes as the rest of the top 10 students. But while each of us had additional classes like band, choir, or drama, she simply took the minimum number of credits, and as a result ended up with a slightly higher GPA. I actually ended up dropping all the way to fifth because I was taking math at a local college (multivariable calculus, linear algebra) which was treated as an ordinary course for GPA.
Somewhat unrelated, but AP courses can often be easier for brighter students as they generally keep disruptive clowns out and offer more engaging material instead of boring busywork. The classes are thus more like college classes and less like babysitting sessions.
1. Normal max is 4.0, school gave extra credit for Advanced Placement and college concurrent courses.