setSpeed() is it the same as initial velocity?

Hi everyone!!!
I using 28BYJ-48 - 5V Stepper Motor// Arduino Uno // AccelStepper
I am trying to measure the time that the program runs with differents setSpeed(), as u can see on the pdf it does not make sense, at least I could not see it.

#include <AccelStepper.h>   
AccelStepper stepper (AccelStepper::FULL4WIRE, 8, 10, 9, 11);
unsigned long x = 2048;
double tiime;
void setup() {
  Serial.begin(9600);
  stepper.setMaxSpeed(600);  
  stepper.setAcceleration(50);  
  stepper.setSpeed(300);
  stepper.moveTo(x);  
}
void loop() {
    tiime = millis();
    stepper.run();
    if(stepper.currentPosition() == 2048)
          Serial.println(tiime); 
    if (stepper.distanceToGo() == 0) 
      stepper.moveTo(-stepper.currentPosition()); 
}

in: AccelStepper: AccelStepper Class Reference
u can find:
"
setSpeed()
void AccelStepper::setSpeed ( float speed )

Sets the desired constant speed for use with runSpeed().

Parameters
[in] speed The desired constant speed in steps per second. Positive is clockwise. Speeds of more than 1000 steps per second are unreliable. Very slow speeds may be set (eg 0.00027777 for once per hour, approximately. Speed accuracy depends on the Arduino crystal. Jitter depends on how frequently you call the runSpeed() function. The speed will be limited by the current value of setMaxSpeed()

References _direction, DIRECTION_CCW, DIRECTION_CW, and speed().

Referenced by MultiStepper::moveTo()."

While I change setSpeed(1,10,20,50,100…) until reaching the setMaxSpeed, it does not matter what is exactly the setSpeed, the execution time remains the same.

I thought that while setSpeed increase, it will take less time to reach the setMaxSpeed, but it looks like it is not this way. It seems that the setSpeed() is useless at all while trying to use it with an acceleration movement.
setSpeed() is it the same as initial velocity? if not, what does exactly work? Am I wrong? While reading the AccelStepper.h that was my hypothesis.

2.pdf (26 KB)

Stepper.run() uses setMaxSpeed() and setAcceleration() and does not use setSpeed()

Stepper.runSpeed() uses setSpeed() and not the other two.

...R

I'd stick to just using setMaxSpeed/setAcceleration/run/moveTo/stop