DoF has absolutely nothing to do with what is actually sharp. It is all about what is acceptably blurred. The standards for what is "sharp enough" vary.
The XA's "snapshot" settings are likely based on 4x6 prints, what the tyro who doesn't understand f/stops and focus is likely to have made. The more detailed DoF tables that Oly provides are more likely based on the then convention of an 8x10 enlargement held at arm's length. Both are conventions dating to the previous millennium.
Today, images are frequently viewed on monitors much larger than 8x10" and many DoF tables and calculators use a higher standard for sharpness ("circle of confusion" was the old metric although some adjustment needs to be made for digital photosite sizes and mosaic array configuration as they introduce additional confusion).