Question about LG HU80KSW Presto

I've been using this thing for a while, but I have a problem. Both in standing mode with a mirror and in ceiling mode, I have the problem that the focus area, the sweet spot (where the writing is really sharp), is limited to about a third of the screen. When I set the focus to what I think is Perfect, I have blurred fonts at the top and bottom edges. Is this normal?