direct offline processing extend and tail feature question

I was under the impression that you could adjust the extend and tail lengths at a later time then when the processing was applied, but when I adjust it, it makes no difference
those features are only active for me if I make the extend or tail adjustments before I apply the desired processing. if I want to change them later i have to delete the processing on the event, make the extend or tail adjustments i want and then re apply the processing, Can you share thoughts please.
also I posted this in the general forum but no one has been able to add any info to it
thank you

I answered your post over there already