I can't make heads or tail of your "more readable" "table". Did you mistakenly used tabs?

Aligning ? and : provides the best results for me. Parens provide a visual scope:

$result = ($major_length == 4800
   ? 18
   : ($major_length == 8552
        ? ($val == 4
             ? 33
             : ($val == 1
                  ? 18
                  : die "not handled")
             )
         : die "not handled"
   )
);
[download]

And then there's Perlish:

; $result = ($major_length == 4800 ? 18
                                   : ($major_length == 8552 ? ($val ==
+ 4 ? 33
                                                                      
+   : ($val == 1 ? 18
                                                                      
+                : die "not handled") )
                                                            : die "not
+ handled"                              ) )
[download]

None of these are particularly readable &mdash or maintainable. if should be used here.