Well:
Let me explain this through GT Express:
1. NDLS DEP: 18:40 (10 MAY)
2. BPL DEP: 5:25 (11 MAY)
3. OGL DEP :1:19 (12 MAY)
Now,...
more... u can see, GT @ 11 May from BPL has started @ 8 MAY from NDLS!!!
TATKAL Quota is same across NDLS , AGC, MTJ, GWL, BPL, ET, NGP etc, just opening day differs.
So, the Quota has been utilized from NDLS or other stations on the opening day itself, i.e. 8 May, leaving WL only!!!
Now, if u have to travel from BPL onwards on 11 May, u should book GWL-BZA (JourneyDate - 10 May) on 8 May, morning @ 8am.
Then @ any PRS Counter, anytime b4 24 hrs of schedule departure, u can get Boarding changed from GWL to BPL!!!!