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<p>The school calculated correctly as long as they followed whatever their published algorithm is for GPA computation. Which algorithm to use (one that weights A-minus by 3.7, or by 3.667, or by 3.67) is a design choice made by the school, but there is nothing to make one choice more correct than another. I guess some people would consider the uniform spacing of letter grades, keeping them exactly 1/3 apart, to be a cleaner design, but that has nothing to do with the issues you’re raising. </p>
<p>As long as Lucy and Desi have their GPAs calculated by the same algorithm, there is no problem of “fairness”. There are some algorithms that could be considered unfair, such as giving very high weight to A’s and very low weight to everything else (winner-takes-all grading), or giving essentially the same weight to all grades C and higher (pass-fail grading), but that doesn’t apply to your situation. You are complaining about some very minor difference between algorithms that produce essentially the same ranking of students, and there is nothing to say that one version is more fair or more correct than the other.</p>