When exporting metadata from Portfolio as a text file, digital asset File Size is displayed in bytes:
When you export file size values as a text file from Portfolio the file size value is formatted as bytes. Computers and software calculate file sizes using two different systems: decimal (Base 10) and binary (Base 2).
In binary terms, 1 Megabyte (MB) equals 1,048,576 bytes.
If you want to convert your exact byte count into binary Megabytes, divide the exported number by 1,048,576
Please check the files file with Notepad or TextEdit and remove all quotation marks before reimporting the file.
You can do so with a Find/Replace with " in the Find field and the Replace field blank.