Here is another technique for you. Just use a split to get the part of the string before the "batch =", then an unconstrained regex match global upon that. Yes, this does have to process the string twice, but the code is clear, short and does not require fancy regex features.

use strict;
use warnings;

my $SYSPBUFF = <<__EOD__;
 run_type = dev,
  max_monitor_time = 0.25
  verbosity_level = 2

  batch =

   (
    source = sample_document_collection_1
    files = Confucius.docx
    dest = Enterprise:Department
   )
__EOD__


my ($top) = split(/\s*batch\s*=/,$SYSPBUFF,2);
my %hash = $top =~ m/([\w\.]+)\s*=\s*([\w\.]+)/g;

print "$_ => $hash{$_}\n" for (keys %hash);

__END__
max_monitor_time => 0.25
verbosity_level => 2
run_type => dev
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