I will be the devil's advocate here and point out something which has been mentioned by the commentators quite a few times, and that is, it gets really easy to score runs in the second innings.... and BNG has always batted in the second innings.
1st ODI - Pak vs BNG - BNG comes really close to a 260+ score
2nd ODI - Ind vs SL - SL were going great guns to chase 300 until some batting errors
3rd ODI - Ind vs BNG - BNG scored 290 in a chase
4th ODI - SL vs Pak - Pak cruised to 190 inside 40 overs
5th ODI - Pak vs Ind - Ind cruised to 330 with two overs remaining
6th ODI - SL vs BNG - BNG cruised to 210 inside 38 overs
Side batting second has won on 4 occasions and the other two they were always in the hunt.... so I think as BNG have benefited with batting last on all their matches they have had an added advantage.