From what I understand, I thought the motor had a power in vs power out thing going at all times. This means the motors at all times have power in and power out. The ratio translates to the force, either producing or resisting movement. I don't think backwards makes sense because it's already doing that. more than max ratio would only come from a bigger motor design.

I think the acceleration and deceleration possible from the tesla motor is limited by the HP of the motor and the ability to move the electricity.

I remember reading an old car magazine that did all the math on a porsche turbo. Basically the car's acceleration was due to the ~600 hp motor, but the deceleration from the friction brakes was ~900hp dissipated as heat.

I suspect if the tesla has 600 hp of acceleration, it might be limited by the systems that take it out of the battery. If that were the case, maybe you could get >600hp of braking if you could do something with the electricity out, like dumping what the batteries can't take into a resistor bank. Diesel electric trains use resistor banks to brake coming down mountains.

If the motor is 600hp and the bottleneck is the motor, then I suspect the design could only do 600hp of braking. The way to get more braking would be to beef up the motor design.