Attacking the insertions in reverse order from the right-hand side means you don't have to increment your position by one for each successive insertion. Swings and roundabouts really but sometimes a useful technique.

$ perl -Mstrict -Mwarnings -E '
> my $text =
>    q{2013020400000000006810083610022013068100200220130688000200494};
> my @offs = ( 17, 6, 31, 3, 3 );
> my @cums = ( 0 );
> push @cums, $_ + $cums[ -1 ] for @offs;
> substr $text, $_, 0, q{-} for reverse @cums[ 1 .. $#cums ];
> say $text;'
20130204000000000-068100-8361002201306810020022013068800-020-049-4
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Here's the code without the PS2 prompt for easier copy'n'paste, as requested by /msg in respect of another post.

perl -Mstrict -Mwarnings -E '
my $text =
   q{2013020400000000006810083610022013068100200220130688000200494};
my @offs = ( 17, 6, 31, 3, 3 );
my @cums = ( 0 );
push @cums, $_ + $cums[ -1 ] for @offs;
substr $text, $_, 0, q{-} for reverse @cums[ 1 .. $#cums ];
say $text;'
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I hope this is of interest.