Uneven servo outputs APM 3.2

Hello All! This is my first question here. I have built a new quadcopter using s500 frame. I calibrated both accelerometer and compass using mission planner. I am having problem with the outputs coming from APM board. The problem is this;

The vehicle stands on its neutral position, all of the outputs are same(1090) for the lowest throttle stick position but when I put slowly the throttle stick up the output values become so different on each motors. For example within a certain position of the throttle stick; 1-2 are almost same(~1600) but 3-4 are one low(1200) and one high(1900). Also, when I change the orientation of the vehicle all motors act the way they should for example when I roll the vehicle right 3-2 output low (1200,1400) and 1-4 output high(1800,1900). Again so much differences in output values. I think these outputs can not drive the quad on air.

Should not it be same for all whichever throttle value on a neutral position of the vehicle? Can it be connected to calibration of the escs because I could not be able to do it with apm. I am having esc calibration problems

Thanks in advance.