if ($counter <= 8) {
        $sum_values[$x] += $ifSpeeds{ $key };
        $counter++;
    } else { 
        $x++;
        $sum_values[$x] = $ifSpeeds{ $key };
        $counter = 1;
    }

##</code><code>##

    $sum_values[$x] += $ifSpeeds{ $key };
    $x++ unless ++$counter % 8;

##</code><code>##

    $sum_values[$counter++/8] += $ifSpeeds{ $key };     # the [] implies int(...)