I think ++Cristoforo has provided the appropriate changes required (in Re^4: Stuck in my final step of code using array of arrays).

Now that I see another example of input and expected output, I suspect 'none' is incorrect for either the start or the end of the range. I originally used this (in Re: Stuck in my final step of code using array of arrays) based on your description containing "... before and after them (if any) ..." in the OP.

Here's another script, that uses virtually the same changes as Cristoforo supplied, but replaces 'none' with the values I think you want. I've included additional test data to cover the four cases with and without codes before and after the special code.

#!/usr/bin/env perl

use strict;
use warnings;

my %special = (PF03797 => 1);

{
    local $/ = "//\n";

    while (<DATA>) {
        my ($id) = /^ID:(\w+)/;
        my @data;

        while (/HIT:(\w+).*?SEQ_START:(\d+).*?(\d+)/g) {
            push @data, [ $1, $2, $3 ];
        }

        @data = sort { $a->[2] <=> $b->[2] } @data;

        for my $i (0 .. $#data) {
            if ($special{$data[$i][0]}) {
                my $start = $i == 0      ? $data[$i][1] : $data[$i - 1
+][2] + 1;
                my $end   = $i == $#data ? $data[$i][2] : $data[$i + 1
+][1] - 1;
                printf "%-41s %7s %4d %4d\n" => $id, $data[$i][0], $st
+art, $end;
            }
        }
    }
} 

__DATA__
ID:A0AWZ5_1___codes_before_only
HIT:PF12951 SCORE:40.0  EVALUE:2.2e-10  HMM_START:2 HMM_END:32  SEQ_ST
+ART:421   SEQ_END:455
HIT:PF03797 SCORE:130.7 EVALUE:3.6e-40  HMM_START:7 HMM_END:261 SEQ_ST
+ART:822   SEQ_END:1073
HIT:PF12951 SCORE:38.7  EVALUE:5.5e-10  HMM_START:1 HMM_END:32  SEQ_ST
+ART:515   SEQ_END:547
//
ID:A0AWZ5_2___codes_before_and_after
HIT:PF12951 SEQ_START:120  SEQ_END:350
HIT:PF03797 SEQ_START:822   SEQ_END:1073
HIT:PF15789 SEQ_START:1515   SEQ_END:1547
HIT:PF00267 SEQ_START:1200   SEQ_END:1350
//
ID:A0AWZ5_3___codes_after_only
HIT:PF03797 SEQ_START:822   SEQ_END:1073
HIT:PF15789 SEQ_START:1515   SEQ_END:1547
HIT:PF00267 SEQ_START:1200   SEQ_END:1350
//
ID:A0AWZ5_4___codes_neither_before_nor_after
HIT:PF03797 SEQ_START:822   SEQ_END:1073
//
[download]

Output:

A0AWZ5_1___codes_before_only              PF03797  548 1073
A0AWZ5_2___codes_before_and_after         PF03797  351 1199
A0AWZ5_3___codes_after_only               PF03797  822 1199
A0AWZ5_4___codes_neither_before_nor_after PF03797  822 1073
[download]