Given equal energy states at the merge, the bandit will quite naturally be slower than you upon completing a 180 degree turn. I think the problem, as Bubi stated, is that there is such a small difference between his reduced energy state and your max speed that he is able to get on your six at 200 with separation between your planes growing too slowly for you to avoid getting shot. You are indeed outrunning him, just not at a very fast clip.
That's what makes WWI fighting very interesting...it's VERY difficult to disengage once fully committed, however it's VERY possible to avoid becoming fully committed, if your SA is constantly at 110%. A dual edged sword...nobody is going to run you down with an LA-7 style on-the-deck monster, but you also don't have the advantage of using one.