public function getMalusFromLoad(Strength $strength, Weight $cargoWeight): int
    {
        $requiredStrength = $cargoWeight->getBonus()->getValue();
        $missingStrength = $requiredStrength - $strength->getValue();
        $malus = -SumAndRound::half($missingStrength); // see PPH page 113, right column
        if ($malus > 0) {
            return 0;
        }

        return $malus;
    }