Yes, and 946 PSI is nothing for an oil field type check valve made for 3K PSI or so. Also, a pump set at 2200' needs to see 946 PSI on start up. Any extra check valves up the line would defeat the back pressure needed to keep the pump from upthrusting on start up.
You are correct a VFD check valve is not needed with a CSV. The varied flow rates from a CSV do not cause a spinning action at the pump like a VFD. Also, many VFD's like the sub/mono drive with the switch are hard on check valves as the check opens and closes every time the subdrive switch makes and breaks. This can cause a check valve to open and close 45 times a minute. For these reasons a
better check valve is needed with a VFD system than a CSV system.