Movement or simulation speed is incorrect
When setting the speed of the motors to a certain value with the function
motor.setSpeed(speed), the simulated speed in MazebotSim is incorrect by a factor of two (i.e. the time it takes to travel a distance of 160mm or turn by an angle of 360° is twice as long as it should take).
This issue was verified by setting the speed of both motors to 100 deg/s, which is equivalent to a linear speed of ~16mm/s, and letting both motors move by 160mm. The forward (linear) travel move takes more than 20 seconds instead of the calculated 10 seconds.
The same issue persists when trying to turn with one wheel standing still and the other rotating. After setting up an angle speed of 20 degrees per second for the robot (this equates to 244 degrees per second for the electric motor), the time to turn the robot to 360 degrees takes ~36 seconds instead of 18 seconds.