nice test - the more i think about, the more i think maybe this is all by-design behavior. so the lesson's are:

1) Called scripts cannot be seamlessly included.

2) Included scripts have to be engineered to be "included".

3) The only thing you would want to put in an included file, are UDF's and maybe global $var declares - else the result is code that has been simply stitched together.

*** Ruud - can you shed any light on these tests/observations ?