I do find similar symptom when guiding through a seperate scope. following link might help answering some of the questions
http://www.stark-labs.com/blog/files/tag-flex.php
I don't think its possible to zero out the flex, but definetely you can improve on it. Once you have done all the things that you possibly can do to reduce flex, Knowing how long you can expose before the error creeps up in the subs will be the key.
Regards
Sad