When building your loop there should be a list of things that come to mind, flow and pressure should be near the top of that list. Pressure drop is the measurement of inlet pressure minus outlet pressure, or the pressure lost of flow through the radiator.
From the pressure drop numbers, we see the RX360 has quite low pressure drop across the entire flow test range. What this means is there is very little flow and pressure energy loss through the radiator and will have very little flow or pressure impact in your loop. You can use an RX in a multi block loop and not have to worry about flow loss or pressure drop.