I actually considered that when writing my original comment but "the mythical man-month" is such an obvious reference that it felt weird to change it. I suppose

I actually considered that when writing my original comment but "the mythical man-month" is such an obvious reference that it felt weird to change it. I suppose you can also think of it like "horsepower", it's an equivalency but doesn't actually mean that the power literally comes from a horse. Still, point taken, I'll consider using person-year next time.