So what you're saying is you'll happily operate the engine beyond its take off torque limitation?
By setting the torque to 64.5 prior to brakes release, then allowing the torque to increase with ram effect, you're not exceeding any engine limitation provided:
1. The torque does not exceed 68.4 psi;
2. The time spent above 64.5 does not exceed 20 seconds.
Refer AFM page 2-6. Note that this is the ONLY way to be strictly in compliance with the AFM.
Some pilots believe the published takeoff figure must not be exceeded at any time during the takeoff. These pilots will set a torque figure slightly less than the published, in the knowledge that it will creep up during takeoff. Their aim is to set an initial torque value that, after ram increase, becomes equal to the published limit.
This takeoff technique is not in compliance with the AFM. If you want to achieve book performance figures, you have to operate as per the book.