Depth of field tables assume perfect lenses, but none are (although a few get reasonably close). Real (actual) depth of field depends on the degree of optical correction. It is one (not the only) reason I never bother with depth of field tables or calculations.
Added to Making Sharp Images are new pages discussing two factors influencing depth of field in real lenses, with examples:
Jon M writes:
Excellent article. Excellent description pinpointing where to look. Excellent, excellent.
Martin D writes:
DIGLLOYD: So many factors influence real-world lens performance. My aim is to show more and more of actual behaviors, since that is all one has to work with for making images.