The secret to the SJ's organized and disciplined?
Well, that's simple to answer. S and especially J.
Downside is the problem with adaptation to new, unexpected situations. That's why they prepare even better, to minimize the chance of encountering an unexpected situation.
The J reaction to an unexpected situation in which they failed: next time I'll prepare for this too!
The P reaction to an unexpected situation in which they failed: why lose time on preparation, the situation will change anyway!