IR will consider WL Position (Serial Number) for considering the clearance!!
1. Low WL vs High WL (Same/Diff Quota/Distance): Low WL may remain unconfirmed, if not available, while High WL get cleared if available in short leg
2. LB Quota: If vacant, will be considered for passenger fulfilling LB Criteria, but thats few berth count.
3. Serial-Wise Clearance: WL position is important & even...
more... in PNR, some may remain WL/RAC. Its like calculation of berth vacant & clearing WL, as per serial with best possible configuration (nearby berth, same coach, nearest coach).
4. For same Journey Leg & Quota, elder fellow with higher WL, cant be cleared first, if LB Quota is exhausted..