j21v3 short target setting range

I am using jrk21v3 motor controller to control a fan (24V-3A). I control it from USB by interfacing with the Pololu Jrk Configuration Utility. I am pretty sure I had everything hooked up correctly (no feedback). I can control the speed of the fan from the “Manually Set Target” bar. I would think that the range of the speed to go from 0 to 4095. However, the fan runs at minimum speed as 2008 and max speed only at 1800-ish. I wonder what else should I do to make the range larger.
I attached here 2 screenshots from the Pololu Configuration. Thank you ahead.

When the feedback mode is set to “None”, the duty cycle target is equal to target − 2048 instead of being the result of a PID calculation. Since you have the input mode set to “Serial”, the slider is directly setting the target value. When the jrk is set up like this, a target of 2648 should correspond to driving the motor full speed forward, 2048 should be brake, and 1448 should be full speed reverse. This is described in the “Feedback Options” section of the jrk controllers user’s guide Please note that since you have the “Invert motor direction” option enabled in the “Motor” tab of the Jrk Configuration Utility, these values are inverted.

By the way, I noticed that you changed the “Current calibration” value from 37 to 40. This value is configured in the jrk configuration utility, but should usually be kept at the default unless you measure currents and determine that the jrk’s numbers are inaccurate.

Also, you mentioned using a 24V fan. Please note that the jrk 21v3 has a maximum input voltage of 28V, and if you are using a 24V battery, it might exceed 28V when fully charged.