xbee communication problem

I have RC controller (Leonardo+XBee) and a tractor (ProMini+XBee)

When I move joystick from center to max forward the weels are speading up in about 2-3 steps. Same if I move joystick from Max to centre.
After receiving a data by ProMini there is one blink of green LED (port 13). Time of blinking and changing speed is same.
I have tried many things like boudrate, changing analog and digital write commands so I have constant integers instead of numerical port numbers, also buffer in the XBee is disabled. None of these made any progress.
Do anybody has any idea what can I try more?

kontroler_20150909.ino (2.1 KB)

traktor_20150909.ino (2.5 KB)