In my opinion, if both suction and discharge pressure is low, it would be refrigerant charging low.But, if suction side is low and discharge is very high, it may block something in condenser tube and exp valve.
Low suction pressure can also indicate poor airflow over the evaporator coil. Get a 608 qualified technician to put a set of gauges onto your system to verify superheat, as well as verifying airflow and fan speeds on the system.
B.E.
You are judged not by what you know, but by what you can do.