Works for any number of files...

#!/usr/bin/perl

use strict; # https://perlmonks.org/?node_id=11119283
use warnings;

@ARGV = <file*.tab>; # or just default from command line
my $column = 0;
my %key;

while( <> )
  {
  my @fields = split;
  $key{ join "\t", @fields[0 .. 3] }[$column] = $fields[6];
  eof and ++$column;
  }

for ( sort keys %key )
  {
  print join( "\t", (split)[0 .. 2], '-',
    map $_ // 0, @{ $key{$_} }[ 0 .. $column - 1 ] ), "\n";
  }
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