We should understand one thing, in Ericsson system there is two parameters work as trigger point when the cell will start carrying HR traffic.
– DTHNAMR ..for NON AMR calls.
– DTHAMR..for AMR calls only.
So, if you set DTHNAMR to 70% for example, this means that when the load on the cell reach more than 70%, the HR traffic will start, mean any new call will be on HR not FR. As sson as the percenatge of IDLE TCH time slots is less than or equal 70% all the traffic on the cell will be on FR not HR.
I suggest to you check the busy hour traffic for the cell and check the traffic hourly on the cell, you will see sure the peak hour is not much so the majority of the traffic will be on FR.
Hope this can help all.