I have a pump. The NPSH curve is:
5280 cmd - 3m
8160cmd - 4.9
10080cmd - 6.7m

The available NSPH and the flow are shown in the figure.
The available NSPH has variation of 0.017 m, but the flow are almost 2500 cmd.

The pump is set up to design point.
Why the flow has such a big variations?