@Sven - The difference between forward and reverse thrust is completely intentional. It is based on the propeller design and both the CW and CCW propellers have the exact same performance. Forward is when the thruster is blowing water out the back over the pointed tail cone. Reverse is when the thruster is blowing water out the front over the nose cone and cable.
For example, if you mount two thrusters side by side, one CW and CCW, and spin them both to push the vehicle forward, they will have equal thrust.
We did this because it has relatively little effect on most ROV applications but provides additional thrust for forward-only applications like surface vessels.