You're not using the transient limits on purpose. That would be pulling transient torque deliberately, or some such. You make the control inputs necessary to make the machine do what you need it to do, and if the N2 moves, so be it. You cannot deliberately change the N2 outside limits if the governor, fuel control, and linear actuator are set correctly. The N2 just does what it does when power is changed. That's why the transient limits are given.