I don't know but it says that local variables are preserved, which means they don't change inbetween wait() calls. So if you assign a value to a variable, wait() isn't going to change it.
It's address isn't preserved after each wait() but in your code you're working with the values of your variables (which stay the same), not their addresses.

But, they are changing.
But only after a few frames, as i observed.