I would call misapplying mathematical tools being bad at math personally. If you said that because you are intergrating revenue back into investments and are showing nx growth you'll get quadratic growth in exchange for cutting growth in half I would call that being bad at math. An uncommon form of it but still bad due to it being a clear failure to model the underlying domain. They did the same thing really by not taking common cause failures into account at all, thinking one can build low risk out of high risks, and more that an ounce of critical thinking could have saved them from.