CStore Essentials unable to support each and every 13 digit UPC Barcodes,
Since 13 digit UPC Barcodes are not considered as recognized barcode, there are some limitations
Only UPC-A and UPC-E Format barcodes have traditionally been used and most recognized barcodes in the United States
This is the reason, with CStore Essentials Price Book, while sending 13 digit barcode Items to POS-Register, some may work and some may not.
Same thing goes with CStore Essentials Item Sales Report, few 13 digit barcode Items may show up under Item Sales Report and other may not be able to generate under Items Sales Report.
Please look into our Help Center article below, for your reference
http://help.cstorepro.com/en/articles/5011640-upc-barcodes
http://help.cstorepro.com/en/articles/4360892-item-sales-report