PCB Shunt BLDC controller current sens
With reference to the datasheet for the MIC4607, you can see that the current detected by Rsns is a latched fault current. This is the absolute maximum (peak) current at which you declare a fault, and all commutation stops.  



If you want to set a LOWER trip point you can use the same Rsns that you have now and set your tripoint to accommodate your design but leaving the fault detection unaltered. There seems no need to provide another sense resistor, simply apply your desired external tripoint and logic functions to the voltage across Rsns.