Tuning the Assassin Optimizes recoil reduction of that cartridge. If you change loads It will change the total recoil reduction, but only a very little (+ or - 1 or 2 ft lbs based on bullet weight and powder charge) but it adds from 10 to 20% over a non tuned brake.
The highest recoil reduction we found in testing every type and brand of brake was an honest 54% the lowest was 37%. the Assassin is not a generic muzzle brake (One brake fits all) It is a Custom brake built and tuned for your particular cartridge, powder and bullet combination to get the most recoil reduction from your particular cartridge.
An example of the difference is present in these Videos.