Ok i think i understand what your trying to say.
There are a few key factors to consider:
Peak Power: To achieve faster acceleration, torque is more important than horsepower. The peak torque is typically reached around 3,000 RPM, and a happy medium for acceleration is usually in the mid-4,000 RPM range for both HP and toque. Although the redline or shift point is close to 6,000 RPM, it doesn't necessarily correspond to the most usable power.
Cruising at Speed and requesting sudden acceleration: When cruising at a constant speed, let's say 60 mph, and the truck downshifts to around 4,000 RPM, it provides instant torque to build RPM and speed, enabling a smooth transition to the next gear. If the downshift occurred at 5.6k RPM, there would be limited usable RPM before the next shift, resulting in a loss of acceleration and slower performance.
Acceleration from 0-60: During a 0-60 mph acceleration, the entire RPM band is utilized to build wheel speed through each gear. The strategy remains the same, spinning just past the peak power RPM, so that when the next gear engages to provide more wheel speed, the vehicle remains within the power curve.
For example, Gear 1 reaches 6,000 RPM, Gear 2 drops to 4,000 RPM to build wheel speed until it reaches 6,000 RPM, then drops to Gear 3 at 4,000 RPM to continue building speed, and so on.
The goal is to optimize acceleration by leveraging torque and staying within the power curve of the engine throughout each gear shift. This strategy ensures efficient use of the RPM band and maximizes acceleration performance.
I hope this answered your question.