For EN_MS_PC and EN_BS_PC its only to enable power control on MS and BS side. so that their power is reduced just so much that they get the desired quality and do not cause unnecessary interference for other mobile stations.
I don’t know which release of Alcatel you are working with or weather they have seperate PC parameters for AMR or not but they could also effect.
Also I have observed in some cases where there is issue with Antenna / Antenna Cabling system the signals tend to die down early and that might be the issue. Check path balance of the TRXs of that cell and DL path of cablinhg.