It sounds like you may have a limiter set for the motor. Have you checked your receiver's manual on how to set and reset limits. These are east and west limits for the movment. Otherwise you have the correct idea of reseting the motor per their manual:
HARDWARE RESET BY RECEIVER
1. Execute the command: Go To Reference (Go To “0”).
2. Cut off the power by disconnecting the coaxial cable.
3. Reconnect the coaxial cable.
4. Execute the command: Shift “0”.
5. Then, its memory erased, the receiver rewrites the satellite table to initial one and corrects the “0”
HARDWARE RESET BY DiSEqC MOTOR
1. Cut off the power by disconnecting the coaxial cable.
2. Press and hold both EAST / WEST buttons for 5 seconds.
3. Reconnect the coaxial cable.
4. LED1 and LED2 blink for 5 seconds.
5. Then, its memory erased, the receiver rewrites the satellite table to initial one and corrects the “0”
I hope this helps you. I have had to do it to my motor and it worked. This is a good motor you have.