No OCR at Numbers beneath Barcodes

Is this a know bug? Or is it a feature?

I have scanned a sales slip into DT3 version 3.8 with automated OCR. I did it with a Fujitsu ScanSnap S1300 and ScanSnap Manager version 7.2 L22.

But, astonishingly, only the text above at the barcode at the end of the frontside of the sales slip is being recognised by OCR. The row of numbers beneath of the barcode is not being OCR’ed. The following backside of the sales slip but again is being OCR’ed properly.

Why that? What can I do in order to urge OCR recognising the whole document?

Do you get the same result scanning using Fujitsu software (independent of DEVONthink) scanning to a file? I presume you scanning to PDF?