Even though this query was intended for Pix but I m sure both of u wouldn’t mind if I share my views aswell 😛
50% of cells below 95% HSR is a huge number…are most of the cells in your network Remote or Urban?
Secondly, you should keep into consideration the fact that you are talking about Handover Success Rate and not Efficiency Rate. So, congestion can be a reason for that.Do check it!
Also, per neighbour parameter tuning is also very important and helps in improving HSR for cells.Check whether the problem is occurring with one or two neighbours or majority of neighbours. If its with majority, you can suspect hardware problem(suma etc).If with one or two neighbours, you need to investigate whether there it.Check possibilty of BCCH Clash and even Co BCCH-BSIC case can be catastrophic for a cell. Also you can harden a handover to the cells with which you are having degraded HSR and ease out handovers to the cells which are having good HSR and high no of attemtps aswell.
As far as DTX is concerned, even though its not advisable to use DTX with AMR in Alcatel….but we enabled DTX with AMR in our Network and considerable reduction in Quality Handover Percentage and Increase in HSR is observed in the Network.Having said that, its still risky because I have witnessed myself the exact opposite of that(increase in Quality handovers after enabling DTX+AMR) in the previous network that i was working on.So, i would suggest that you first implement it in a small scale and if its giving good results, you generalize it.