The good and bad thing about improvs are that they rely on one's memory.
So for repeated sections:
good: faulty memory can lead to either playing something completely different or improving on the previous version of the section because you can't completely remember it.
bad: the exact same thing, but when you make things worse.
For the life of me, I couldn't quite remember the chord progression I used the first time through. And I liked it. So it makes an appearance once, then vanishes.