When I ran your program I got error as "Useless use of split in void context at..." So I changed the code little bit, please have a look at, below, it works fine now.

#!/usr/bin/perl
use strict;
use warnings;

$,="\t";
open(IN,"<hcspln_plforecast.txt");
open(OUT,">plforecast.txt");
$_=<IN>;
$_=<IN>;

while(<IN>) {
    y/"//d;
    if(/^No_Company/) {next;}
    s/#Mi/0.00/g;
    my @Array = split(/,/);
    if($Array[1] =~ /CC_/) {
        if($Array[5] =~ /^PL_/) {
            $Array[0] =~ s/COCD_//;
            $Array[5] =~ s/^PL_//;
            print OUT $Array[0],$Array[1],$Array[5];
            splice(@_,0,8);
            print OUT "",@_;
        }
    }
}
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Here, I used @Array variable to hold the splitted values.

As you have not given as sample input file content from hcspln_plforecast.txt assumed as follow and test the script.

line:1
line:2
COCD_1234,CC_line3,c,d,e,PL_line3
COCD_2344,CC_line4,h,h,i,PL_line4
[download]