Issue:
On Landscape -> (Normal Page Mode), when user activates "Zoom" function, the zoom slider is already at 9/10 of the way to max, and merely correlates to 100% zoom. So max zoom is limited to around 110% zoom. This effectively renders zoom in landscape mode useless.
Work Around
On Landscape mode, press the magnify button. Press Page Mode, select a page mode other than Normal. Press Magnify button, Press Zoom In. Now you can zoom considerably more. The zoom slider is no longer already at 9/10 of the way to max. It is about 3/10 of the way to max, thus leaves considerably more room to be increased.
Zoom Bug:
On some documents, the contents of the page will simply disappear before the zoom slider can be adjusted to maximum zoom.
There you have it, there's even a bug with-in a bug.
Someone at Sony watched Inception too many times. ANother incompetent product from Sony.