I'll try to parse out my problem laconicly:
I've two separate urls formatted as csv files that I want to import to the SAME content-type.
I'm using the same Feeds importer to accomplish this task, using the same unique identifier to import each url and update/overwrite all existing nodes.
Yet, for some reason I'm still getting new nodes when I should be getting updated nodes.
I have no clue where the process could be going wrong hence my post herein. Any help would be most emphatically appreciated.