Hi Iron,
Welcome to Auctiva. Only listings that you post through Auctiva will count against the 15 listings per month that is allowed under the Starter plan. Therefore, any listings that you post directly through eBay's "Sell your Item" form will not count against this allowance.
If you have any other questions regarding your Auctiva account, please feel free to contact our customer support team using the web form on the following page of our site: http://www.auctiva.com/help/requesthelp.aspx
-Mike