Agreed. Once PTSD is present, the problem is that something that happened as a child, or outside the military period, that you never thought about again, now comes back and haunts you as a trauma in your life. PTSD really will use everything and anything it can find against you to keep producing symptoms and knock you over. Once you get control of it though and learn how to maintain it, via experience... then it does get easier.
This is why I put an average timeline on a couple of years, ranging out to 5 years... being the last few years are gathering experience from all the work done in the first couple, tweaking your lifestyle choices and how you react to things.
I solved a lot of problems in those first two years of solid hard work, self analysis and experimenting with different therapy models, using exposure, etc... and I got a hell of a lot better, however; the past 3 - 4 years is where I have really refined myself based on everything learnt in those first two years. This being what I call, the experience stage.
Then regardless of all of that, you must factor and accept, relapses during all of it. There will be times you fall over, shutdown, etc... but using everything you learn as you go, and experience, will dictate how long or short those periods are.