All I know is these are the charts they sent and said they are open volt no load tests. If you are getting something different then I will have another dispute with EFFSUN on this. My 600 watt is 600w at 28 volts at 480rpm at 17 mph with 2.8ft blade set. But Amy Zhang told me that those charts are not how they rate the pmas. They do not put blades on and run in a wind tunnel with a 24 volt battery system on it to test for output. They design the PMA for 28 volts, Then they run open volt and shorted current tests and come up with the RPM to Watts chart. Where as Windy Nation tests are with a load on them. Better real world test.