That type of duplication was seen with the version that was provided for download in the plugins area, but is corrected in the version discussed over the last several pages and is to make its way to the plugins once a few other improvements are made to expand its functionality and interoperation with other "typical" software.
Anyways, suggestion is to apply the software available at
https://github.com/mc12345678/Stock_...butes_Combined. The files in the includes and admin directories should be applied first (merged as applicable), then to go into the sub-folder for your version of ZC and the files/changes also applied/merged with your template.
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