protected function offsetMonthInDate(Carbon $original_date, $offset)
    {
        $original_month = $original_date->month;

        // Calculate expected month if offset is positive.
        if ($offset >= 0 && ($original_month + $offset) <= 12) {
            $expected_month = $original_month + $offset;
        } elseif ($offset >= 0) {
            $expected_month = 0 + ($offset - (12 - $original_month));
        }

        // Calculate expected month if offset is negative.
        elseif ($offset < 0 && ($original_month + $offset) >= 1) {
            $expected_month = $original_month + $offset;
        } elseif ($offset < 0) {
            $expected_month = 12 + ($offset + $original_month);
        }

        return $expected_month;
    }