BasketItemBase::setField

public function setField($name, $value)
{
	if ($this->isCalculatedField($name))
	{
		$this->calculatedFields->set($name, $value);
		return new Result();
	}

	if ($name === 'CUSTOM_PRICE')
	{
		if ($value == 'Y')
		{
			$this->markFieldCustom('PRICE');
		}
		else
		{
			$this->unmarkFieldCustom('PRICE');
		}
	}

	return parent::setField($name, $value);
}