Difference between ERPM and Duty Cycle

Hello,

I am looking to better understand the difference between ERPM and Duty cycle, when I log data on my board and overlay the Duty Cycle and ERPM, they seem to be doing the same things. What is the difference between these two parameters? 

What is the difference between "Duty Cycle Current Limit Start" and "ERPM Limit Start"?

Is it possible to limit motor current consumption at maximum speed? I am looking to allow for short, high burst currents during acceleration and climbing but when the motor is running at full speed, peel back the current to help reduce motor temperatures. I am running in "Current, no reverse with brake" control mode. 

Thank you guys!