The Delta Load is the change of throttle position over a 10ms time frame. This is the rate of throttle position movement.

A fast throttle movement could have a TPS rate of change of 15% this means that in a time frame of 10ms the throttle position moved 15%. A slow throttle movement could have a TPS rate of change of 1%, which means that in a time frame of 10ms the throttle position only moved 1%.