Problem with autopilot

Hello everybody!
i have a problem with a plane i am working on, even if in the autopilot the default_vertical_speed is set to 1800, when i change altitude the max descent speed is around -1000 and climbing it is around +1200.
If i move a bit the vertical speed knob, like 1700 and then 1800 again, the plane get the right vertical speed of 1800.
Looks like it ignore the value, until i move and set it.
I am going crazy since i'm trying lot of settings.
Any help would be really appreciated! Thanks
Make sure you are not using a system that requires you to 'set' and 'activate' your VS setting. For instance, on airliners, you dial in your VS, but you need to activate it, like 'Push to Arm'. Othewise, it uses its base setting that is in the 'aircraft config'. If you want to change the 'default' VS for AP, then go to the aircraft config, into its autopilot section and reset the VS to 1800. Then it will always use that as its default VS speed.

If you are making your own gauges, make sure your AP coding is using the right command (event) strings to operate VS. Dont use the 'setting' system which I just talked about, if that is giving you a hassle.