रेलफैनों को आता है ज़िन्दगी का मज़ा लेना

Ticket Reservation
Transaction ID: 0370000165 PNR No: 6161266041 Train No. & Name: 12245/HWH YPR DURONTO
Date of Journey: 11/10/2011 Date Of Boarding: 11/10/2011 Class: SL
From: HOWRAH JN(HWH) To: YESVANTPUR JN(YPR) Boarding: HOWRAH JN(HWH)
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Upto: YESVANTPUR JN(YPR) Distance: 1946 KM Scheduled Departure: 11:00
Total Fare: Rs. 1610.0 Adult: 3Child: 0
Details of Passengers
SNo. Name Age Sex Status Coach Seat/Berth
1 P K VENKATRAMANI 061 Male /CONFIRM S5 0051/UB
2 UMA VENKATRAMANI 056 Female /CONFIRM S5 0049/LB
3 S KRISHNAMBAL 081 Female /CONFIRM S5 0052/LB

How is this possible ? 51 is UPPER BERTH and 52 is LOWER BERTH. AFAIK 49 and 52 are lower berths but how come 51 which should be middle is shown as UPPER. Incidentally, I had indicated berth choice as lower for the 2 ladies and upper for myself. So the allottment as desired. Bur the berth numbers appear to be skewed. Any explanations?