Case number and interview dates

[alkeshchokshi]

Hi,
My case number is BMB199676xxxx and I have been filled under the F4 category.
Just browsing through the interviews scheduled at Mumbai consulate, I found case numbers with bmb1993xxxx to BMB2006xxxx.
What does this mean? doesn't 1996 in the case number mean the yr in which the case was registered with NVC.
Then how come cases of 2006 being given interview dates.

Thanks

Alkesh