If you use a particular version of each letter at each size, you start to accumulate positioning error as you go along a line (or end up with odd gaps if you tr

If you use a particular version of each letter at each size, you start to accumulate positioning error as you go along a line (or end up with odd gaps if you try to avoid it). Nowadays, we tend to aim for precise reproduction of the font's sizing, even where the size ends up not being a round number of pixels, for consistency. You'd then need at least 16 versions of each letter to approximately cover each subpixel position, and it starts not really being a win.