PID Speed Mode not limiting max ERPM

I have an electric wheel barrow motor that i am using on a tugging device, essentially its pulling heavy loads at low speed. I want to use PID speed mode and set my ERPM limit at a walking pace cause i don't want it to be able to go any faster. When i am at 5k erpm and i try and push it faster it actively brakes to keep the motor at 5k erpm, however when i get up to 10k erpm and try and push it faster it allows me to push well past 10k erpm even when i let off the throttle completely. Then when it comes down below 10k erpm it will resume its braking. I really need the cap at 10k erpm and i just cant figure out how to do it. 

Thanks!