Meathead's right, it's just a fact of online gaming. The good news is it goes both ways, as he stated.
You've just got to assume anything you see regarding other planes' gunnery is an approximation, nothing more. The better the ping times are on both ends, the closer of an approximation it is. When all is said and done though about all you can say for certain when you see or hear the bandit's guns firing, is that he's shooting at you. Where the tracers are on your end is almost meaningless.
When I'm defensive against another plane, one of the main things I keep in mind is they've always got a slightly better gunnery position than it appears they have. I err on the side of caution to make sure I'm out of their way, but it makes getting the shot on the overshoot a lot more difficult.
Wiley.