Blindwrite is not accurate in reading out CD size

IN blindwrite 5.2.23, in the copy CD dialogue it shows my Cd as being 509MB. When i go to the BW5 image it shows it as being 540, or around there. Also i went into NERO and for disc info saw it as that bigger size, not 509MB. So my question is, why is Blindwrite not accurate in giving correct CD sizes?

CD images from programs like BlindWrite/CloneCD/Alcohol contain more info than just the file system of the disc. They contain topology & sometimes sub-channel data to try to reproduce a 1:1 copy of the original.

As for Nero not showing the same CD file system size as BW…that might have to do with the way they are calculating a MB…whether its 1,048,576 bytes or 1,000,000 bytes or 1,024kB or 1,000kB, etc…