listed ac motor horsepower doesn't match voltage and amperage
You need to consider both efficiency and power factor. Output power = V X A X eff. X pf. 0.44 is not unreasonable for eff. X pf, but it would probably be higher for a modern motor. Service factor is allowable sustained overload. You can operate a motor at the service factor without any immediate bad effects, but it will be running hotter and a lot of operation at the service factor will result in a shorter than expected service life.