If the system uses the vacant PQ berths to provide end to end accomodation, does this not mean PQ is end to end? As you know (the same IRFCA site), that a ticket cannot span across 2 quotas in 2 legs of the journey and give a confirmed berth to passenger. If a confirmed berth has to be given to a passenger, it has to be from "one single quota only in which the passenger fits in as per his source-destination of journey". So now you yourself have said that end to end accomodations are provided from PQ.
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Btw...
more... - r you ready to share the cancellation charges and irctc service charge? Infact, if it does not come out as per what I say, I will not even charge you.