Size difference EAN13 .eps and .pdf files linked in Adobe Illustrator

When using an EAN13 barcode saved as .eps in Adobe Illustrator, I noticed a slight difference in size after embedding that barcode file.

I sometimes place a white rectangle above the barcode (for additional codes) and after embedding the barcode is slightly larger. This problem does not occur when using barcodes saved as .pdf.

Note: The embedded and linked barcode size for both .eps and .pdf formats are also slightly different to the size in the preview window of the Barcode application.