Map update 2008 city Navigator Europe NT upgrade paths diferances?

Can someone tell me what the difference is between the following 2008 city
Navigator Europe NT upgrade paths:

1) Map update (part 007-01397-00 RevA) this is the totally automated version
with the eight digit key number and 5.21GB of data on the DVD

2) The version Garmin support send out on a recorded DVD which requires the
Mapsource program to transfer the selected maps to the Garmin GPS to be
updated and uses a twenty five digit key number, but only has 1.41GB of data
on the DVD