Dates in P6

Dear All,

I have this data in P6:

Start Date: 29-Sep-08
Finish Date: 20-Feb-11
Actual Start: 29-Sep-09
Actual Finish:
Early Start: 26-Jun-09
Early Finish: 20-Feb-11
Late Start: 30-Sep-08
Late Finish: 02-Apr-12
Total Float = 324
Data Date: 26-June-09

Strange! Why is the early start 26-Ju-09 when the activity started already? Why is the late start 30-Sep-08 when the total float is only 324?

Please let me know the reason whoever notice the same.

Many thanks,
Scarlett