First thing to check is battery power level, and for good connections. Then check the speed of the legs with no weight on them. If the speed is the same loaded and unloaded, and the battery and connections are good, it would appear that your dealer is correct.
Many of the electric front legs are very slow due to the fact that the motor is way underpowered for the amount of work required of it. Some people have added a motor to the unpowered leg, and some, like me, have removed the OEM legs/motors and gone with a different system entirely. Like the
Bulldog Jacks.