when using the blue list to get a key, why do i choose corp in the software and not pro (or home if theres an option)??

im going on the instructions listed here:
http://www.trwhotfilez.kit.net/xpsp1....html#Generate

how do those keys differ from the instructions listed here?
http://www.tweaktown.com/document.ph...=guide&dId=350

TIA