no need of tatkal. its something like your ticket is from Raipur to howrah in Mumbai-Howrah express and ticket is showing status as the chart is prepared at Mumbai and confirmed from there itself. For your ticket chart may be prepared at Nagpur or raipur and the status remains same. Probably there was a booking from mumbai to raipur and the next leg journey which fell vacant has been allotted to you.
Note: Just for example, i have quoted these places, hope its fine for you:)