May I append another question I just run into?

It seems that it is not possible to call a subroutine with GOSUB from inside a Function? I get an error 'Label [xyzSub] not found'

The opposite however works fine, you can call every function from inside a function.

a) Could a KIX expert tell whether I am mistaken?

b) The SUBROUTINES may alter variables which were declared as globals whilst functions, as explained in the previous posts, have no chance to do so.

Both considerations may help deciding whether to implement code as function or as subroutine.

Thanks for all your valuable hints. Rosario