Mechanical Power (Application) and Electrical Power (Stepper Motor) Discrepancy
To much text for a comment.


Your link leads to 6 differnt moters, none of them is listed with 0.3 &Omega;
You can not use the DC resistance to make power calculations
The inductance is not stable, it changes with speed and load
Stepper motors are supplied with a pulsed DC voltage/current, that makes power calculations a lot more difficult than with DC or AC currents
Stepper motors have a bad efficiency, if the diagram above has no bugs, it shows a situation with Pm = 46.2 W and Pe = 305 W (Eventually this is peak and not average power)


I don't think that i'm wrong when i concluded that you will need a lot of profound electrotechnical and mathematical knowledge the make reliable calculations with stepper motors.