When I filter todays date for hands played I receive all the hands played for that level. Example: I have 11,400 hands at NL25 and have played 100 today. When I filter NL25 on 5/15/08 I see stats for 11,400 hands.
I've noticed that it only seems to be broken in the general info section, if you check the other sections like sessions or the graph you'll see that it's filtered correctly.
If you wanted to see what stats you ran you could go to positions.