1) The dots only show at relatively short distance compared to full labels.
I am going to say the opposite ... on my system dot labels do not show at close ranges but only at long range when the game would normally show you nothing (no airplane on screen as it is too far away to register even a pixel on your screen). Once the game starts drawing an aircraft then the dot label disappears. I have dot labels set at 5000 (metres?) in workshops so will see a black dot in the sky for a plane at about 5 km, and then when it gets to about 2.5 km from me I see it switch to a coloured dot (usually greyish) and that is the game now actually drawing the plane on the screen.