Problems with the output of the controller

Hi ! I have an issue with the control of my servomotors.

So this is my mixer :

Small foil mixer

Two scalers total (output, roll).

The mixer is configure as a pass through.

M: 1
O: 10000 10000 0 -10000 10000
S: 0 0 10000 10000 0 -10000 10000

I think I understood how mixers work and I sticked to a regular one but I logged the data and as you can see above, when my variable ACTUATOR_CONTROL_TARGET is 0, the variable that is sent to the servo, port0_SERVO_OUTPUT has a weird offset of 1500, and varies between 1000 and 2000 when ACTUATOR_CONTROL_TARGET varies between its extreme values. I don’t understand the relation of this with the mixer I used. Could someone help ? Thanks

1500 is the width of the pulse at the centre (zero) position of an rc servo 1.5ms
1000 and 2000 are the min and max widths that give you -100% travel and +100% travel…