PID settings do not go below some minimum

Hi. I am testing my hexa copter (APM Copter 3.4.5) mounted on table. For testing purposes I lower stabilize Ps to zero. The problem is I can not lower them below 3.0 anymore. I was able to set them to 0 once and was testing as I needed, but after I raised them to 2, it became the minimum. Then I raised them to 4 and now the Mission Planner will not allow me to go below 3. May be it happened after update, I do not remember.

Is Mission Planner limiting values we can set? Or is it the firmware thing?

if you need to change the values lower, please use the full parameter list. this is by design to stop any accidents.