The extra 2 GPM shouldn't blow the valve or damage the pump, because the pump goes into lower flow at higher pressures. It will create some restriction in the valve forcing the pump to little higher pressure when flowing at low pressure. Way to find out how much restriction the valve creates is tee in a guage at inlet of the valve and run the pump at full open flow (no spool function) then put the guage at outlet and do the same test. Difference in pressure readings is the restriction of the valve.