Not just cancellations from Hosur, the following will make your chances bright:
1- cancellation of passengers, ahead of you, first eligible for PQ
2- Vacant segments of berths detected during charting.
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Ideally you should...
more... have checked whether berths from Bangalore to SC were available when you booked. You could have booked 2 tickets then : Hosur to SBC, and SBC to SC.