Are you sure it works this way ? I think the 70% corresponds to the load limit at which the calls are being established in HR.
For instance, if this threshold is set to 70% :
from 0% to 70% of TCH load (number of busy TCH / total number of TCH), calls are setup in FR.
If the load is greater, then the new calls are established in HR.
When the TCH load goes below another threshold (usually 30% or 40%), the calls are established in FR again.
Maybe i’m wrong for ericsson, though…? They implemented it in a special way ?
You can try to decrease 70% to 40%; and see what is the effect on the ration HR/FR.