ARP Studs: Undercut vs. Standard?

[rfkellner at snet.net (Rick Kellner)]

ARP lists two types of studs for VW heads, one set is a "Standard" set
and the other is an "Undercut" version.  A brief description from a
vendor's site briefly describes the difference.   Other than the brief
description below does any want to add some information to clarify the
benefits?  BTW, the cost difference is $15 however; still trying to
understand the benefits and how.
Thanks, Rick.
 
"You will also note that ARPR offers specially undercut studs for
several engines. This procedure (done only to the shorter studs) more
equalizes the "stretch" of both studs, which makes for a more consistent
clamping force-one that compensates for head gasket compression when the
head is installed. This helps prevent blown head gaskets, and assures
optimum sealing!"
 
Link to the two sets
http://www.nolimitmotorsport.com/prod/arp-204-4204
http://www.nolimitmotorsport.com/prod/arp-204-4702