I tested your code with Spreadsheet::Read 0.63 on my Win XP Active Perl 5.20 installation and it works fine. I did have Spreadsheet::ParseExcel already for other reasons. That may be the "trick".

$Options = {
             'dtfmt' => 'yyyy-mm-dd',
             'attr' => 0,
             'strip' => 0,
             'rc' => 1,
             'cells' => 1,
             'clip' => 1,
             'debug' => 5
           };
Opening XLS $txt
    1 sheets
    Sheet 2 'test' 2 x 7
-35,-39,-39,-60,-35,-39,
-36,-40,-40,-59,-36,-40,
[download]

I've been using a different reader, Spreadsheet::DataFromExcel for simple .XLS files (won't work for .XLSX), real easy to use, here is demo:

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

use Spreadsheet::DataFromExcel;
use Data::Dumper;
    
my $p = Spreadsheet::DataFromExcel->new;
    
my $data = $p->load('Test.xls', 'test',0) or die $p->error;

foreach my $rowref (@$data) #$data is ref to an Array of Array
{
   print join (',',@$rowref), "\n";
}

__END__
-35,-39,-39,-60,-35,-39,-39
-36,-40,-40,-59,-36,-40,-40
[download]