The TDH (Total Dynamic Head) of a system is related to amount of power required to move the water through a system at a specific flow rate.
For example, a flow of 120 gpm at 67 feet of head requires about 1.514 kW (kilowatts).
In the graph, we can see that the pump actually uses 3.0 KW.
So, the pump uses 3,000 watts (4.023 HP), to deliver 1,514 watts of power (2.0303 hp) to actually move the water.
The efficiency is 1.514 kW/3 kW = 0.505 = 50.5%.
The 1,514 watts is the actual power required to move water through the system due to friction.
The rest (1,486 watts) is due to inefficiency and energy loss from things like motor heat etc.
1,514 watts is 5,166 btu/hr, which could add 0.0861 degrees Fahrenheit to the water at 120 gpm if it all turned into heat.
3,000 watts is 10236 btu/hr, which could add 0.1706 degrees Fahrenheit to the water at 120 gpm if it all turned into heat.
Below is for the IntelliFlo, which shows a THP (Total Horsepower) of 3.95, but a HHP (Hydraulic Horsepower) of 1.88, which is 1.88/3.95 = 0.47595 = 47.595% efficiency.
The full load amps is 16 at 230 volts, which is 3,680 watts (3.680 KW) compared to the 3.2 KW shown.
3,680 watts is 4.92 HP compared to the 3.95 shown, so they have some leeway in how they report their metrics.