Distributors and retailers might different requirements for your EAN barcode. Be sure to check with them before approving your cover design. Here is a list that was sent to me from one of my customers distributors.
EAN Barcode Placement on Back Cover
(1) Bar Code: Only the EAN 13 bar code will be permitted on the back cover. The UPC bar code is not to be printed on the back cover/cover 4.
(2) EAN 13 Bar Code: The EAN 13 bar code must appear on the back of the book and include the isbn printed out in a consumer readable format above the bar code.
(3) EAN 13 Bar Code Price Extension & Price: You must now include the price in the EAN bar code price extension. Many publishers have not been including a price in the bar code extension. This is now a requirement of our major customers.
(4) Consumer Readable Price: There must be two US prices on the book. The first is in the bar code as mentioned above. The second is a price that i s printed somewhere on the back of the book in consumer readable format in 9 point or larger font. If there is just one currency shown on the book, it could read, for example, $12.99. If there is more than one currency it should read US $12.99.
(5) Bar Code Size: The size for EAN 13 bar codes can be no smaller than 7/16″ x 1 3/4″ wide. This is a new requirement by our accounts, including Barnes & Noble. Some publishers have been told by international designers/printers that the bar codes can be smaller. They must meet this minimum size or NBN will be charged for stickering to the compliant size and NBN will rebill you.
(6) Placement: The EAN bar code must be located on the bottom right corner of the back cover.
Finding the time to research your market and get info from others can help you determine the best ways to move forward. I offer full book design for cover and interior, branding and informational consulting sessions for self publishing authors