I was a little confused by the conversion factors you showed. The characteristic performance curve of a pump shows the relationship of the flow rates against the respective differential heads. The reason we use the differential head and not pressure is so that the curve will be applicable to all liquids of different densities. When a pump is tested, the pressures are normally identified in pressure readings, which are, in turn, converted to head using the density (or specific gravity) of the tested liquid. Flow rates do not require correction. Nor does the minimal difference in rotational speed. I am unsure of how the heads you identify were converted, but it will require the use of the density at the higher temperature to convert from the pressure reading on the test bed to the resultant Head to be used to draw the performance curve.
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