Or if you prefer, lines of integration/disintegration.
At first I thought this meant that when you're stressed you'll act like the bad qualities of a certain type, and to develop yourself you need to act more like your growth type, but I'm not so sure that's true.
The stress part seems to hold true. I see myself rushing things when stressed, avoiding pain like a 7 sometimes, and when I do I calm myself and go back to normal. However, I act like an 8 when my competence is satisfied, my basic desire. I stop feeling so anxious, I stop shaking, stop stuttering and being so quiet.
I get some of 8s low points as well, being too bossy, spending too much time 'gathering resources', Getting too angry to the point where it just fuels the fire and everyone starts fighting.
I think being at your best is separate from your lines of integration/disintegration. I know I'm at my best when I'm calm, focused and in control, without anger. In such a state, I can nearly do as a good 8 would, looking after everyone's needs and being in control of life instead of asleep to it.
If I ever get time, I'll probably have to read up on this carefully.