Indeed, in some langages the do is executed first. This is mostly becasue the while(condition) is place at the end. In Fortran, it is placed at the begining so this explains that -- good reference nonetheless!
You are right on your second point too. As I said at the begining the golden rule is to let TELEMAC do the parallel part so you do not have to worry about anything ...
( TELEMAC is so powerful
).
Glad this has helped.
Sébastien