my $old_cust_data_href = load_old_cust_data($old_cust_data_file);
my $new_cust_data_href = load_new_cust_data($new_cust_data_file);
my $result_hash_ref = data_compare($old_cust_data_href, $new_cust_data_href);
# ...

##</code><code>##

my $old_cust_data_href = load_cust_data($old_cust_data_file);
my $new_cust_data_href = load_cust_data($new_cust_data_file);
my $result_hash_ref = data_compare($old_cust_data_href, $new_cust_data_href);
# ...

##</code><code>##

my $cust_data_href{$_} = load_cust_data($cust_data_file{$_}) for qw /old new/;
my $result_hash_ref = data_compare($cust_data_href{old}, $cust_data_href{new});