What that would appear true in theory, not all fonts can be rendered at all point sizes. For example, consider a Label "label1" with initial font "Microsoft Sans Serif" at point size 8.25.

        Font f = new Font(label1.Font.FontFamily, label1.Font.SizeInPoints + 0.5f);
        label1.Font = f;
        label1.Text = label1.Font.SizeInPoints.ToString();

Execute that code a few times (at least on my WinXP machine) via a button click or whatever, and the font's appearance at 9.25 and 9.75 are identical, as are 10.75 and 11.25, etc. Also, there is obviously some mapping going on, setting the font size to 8.0 results in 8.25, 10.0 to 9.75, etc. Is there any way of knowing, short of trial and error, if changing the point size by some amount will actually have impact on what is rendered?