Thanks! Those are much shorter ways of splitting and dealing with the 10s. My method of summing is a bit shorter, so that gets me to 105:

sub bowl {
    ($_,$n)=@_;
    s#(\d)(\d|/(?=(.)))|X(?=(..))|.#
    ($3.$4?"X$3$4":$1.$2,"")[9<$n++]#ge;
    s#./|X#9#g+map{(3)x$_}/./g
}

chomp( @ARGV=<DATA> ) if ! @ARGV;
for my $line ( @ARGV ) {
    print "$line = ", bowl($line), "\n   ";
    for(  0..9  ) {
        print " ",bowl($line,9-$_);
    }
    print $/;
}
__END__
81633470434/72813/62
81633470434/72813/X18
X00X00X00X00X00
00X00X00X00X00X00
X11X11X11X11X11
11X11X11X11X11X11
5/63XX7043X4/813/6
[download]

The |. on the end of the first regex is required so that the regex matches the entire string. Take a 5-frame game as an example:

6/ 45 X  7/ X3/
14  9 20 20 20
14 23 43 63 83
"6/45X7/X3/"
"6/" matches; $1="6", $2="/", $3="4"; change to "X4"
  "45" matches; $1="4", $2="5"; change to "45"
    "X" matches; $4="7/"; change to "X7/"
     "7/" matches; $1="7", $2="/", $3="X"; change to "XX"
       "X" matches; $4="3/"; change to "X3/"
        "3" matches; change to "$1$2" eq ""
         "/" matches; change to "$1$2" eq ""
(result: "X445X7/XXX3/")
[download]

If we required that unused bonus frames be recorded as "-", for example, we could get even shorter. For example, this 86-stroke version:

sub bowl {
    $_=pop;
    s#(\d\d|.(/))(?=(.))|X(?=(..))|.#$2.$4?"X$3$4":$1#ge;
    s#./|X#9#g+map{(7)x$_}/./g
}

chomp( @ARGV=<DATA> ) if ! @ARGV;
for my $line ( @ARGV ) {
    print "$line = ", bowl($line), $/;
}
__END__
81633470434/72813/62--
81633470434/72813/X18
X00X00X00X00X00--
00X00X00X00X00X00
X11X11X11X11X11--
11X11X11X11X11X11
5/63XX7043X4/813/6
[download]

Yes, but since you're now counting the frames (and replacing ./ and X later) you don't have to match the whole string!
Much simpler ( 84 chars):

sub bowl {
  ($_,$n)=@_;                                      # 11

  s#./(?=(.))|X(?=(..))|..#$&.($n++<9&&$1.$2)#ge;  # 47

  s#./|X#9#g+map{(1)x$_}/./g                       # 26
}
#                                                   ___
#                                                    84
[download]

And here's a little bit more complicated one which passes strict and -w (and yes, I do have other things I'm supposed to be doing with my time):

sub bowl {
  $_=pop;                                          #  7

  $a=()=/\d\d\B/g;                                 # 16

  s#(?=./(.)|X(..))#$a++<9&&($2||$1)#ge;           # 38

  s#./|X#55#g;                                     # 12
  s/\B/+/g;                                        #  9
  eval                                             #  4
}
#                                                   ___
#                                                    86
[download]

update(5sep): Actually, here's a pretty straightforword one for perl 5.6.0 and higher that passes -w and use strict at 85 chars:

sub bowl {
  $_=pop;                                          #  7

  m#(./(?=(.)(?{$_.=$2}))|X(?=(..)(?{$_.=$3}))|..){9}#;
                                                   # 53
  s#./|X#55#g;                                     # 12
  s/\B/+/g;                                        #  9
  eval                                             #  4
}
#                                                   ___
#                                                    85
[download]


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