burning fedor dvd iso using wodim

[JD]

I burned the fedora 12 dvd iso twice using wodim.
Both times, it wrote:
3738959872 bytes (3.7 GB) copied, 511.982 s, 7.3 MB/s

whereas the size of the actual iso is
3738935296 bytes - a difference of 24576 extra bytes written,
and this in spite of providing the wodim argument -nopad

Is this "normal" behaviour of dvd burners?