I see. Seems like error of calculation is lesser if ordered turning angle is lower. Perhaps repeating several times all at once *move unit to a point and facing wanted angle*? Didn't check it myself though. For 90 degree turn I had to add exactly 10.20 degrees, so instead of Facing Angle + 90, I used 100.20 degrees and error was almost completely eliminated. I checked with displaying facing angle with text, it still seems to vary ±2 degrees both ways. I guess I still will have to use your method, thanks.