I think I might be inclined to an oH instead of an oA:

>perl -wMstrict -le
"my @class = ( 40,  40,  40, 183, 183, 259, 244, 503);
 my @qty   = (260, 234, 211, 301, 401, 321, 210, 451);
 my %bin   =  map { $_ => { class => 0, qty => 0 } }
              0, 40, 183, 503, 442, 259, 244
              ;
 for my $i (0 .. $#class) {
   $bin{ $class[$i] }{class}++;
   $bin{ $class[$i] }{qty}  += $qty[$i];
   }
 for my $key (sort { $a <=> $b } keys %bin) {
   printf qq{%4d => [%2d, %4d] \n},
          $key, @{ $bin{$key} }{ qw(class qty) };
   }
"
   0 => [ 0,    0]
  40 => [ 3,  705]
 183 => [ 2,  702]
 244 => [ 1,  210]
 259 => [ 1,  321]
 442 => [ 0,    0]
 503 => [ 1,  451]
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