Here's a similar approach:

# snip

my %hash;
$hash{$_}=1 for (@updatelist);
$hash{$_}=0 for (@storelist);

for (keys %hash) {
  push @finallist, $_ if ($hash{$_});
}
[download]

ie: "make list of new addresses, but cross off those already used".

..02

cLive ;-)