Custom price is not getting calculated on cart magento 2

Question

I am setting up the custom price with some calculation during add to cart and update cart.

I am using following code to add custom price

$fPrice = 39.1467 // after calculation 
$qty = 24;
$item->setCustomPrice($fPrice);
$item->setOriginalCustomPrice($fPrice);
$item->getProduct()->setIsSuperMode(true);

Magento 2 calculating the row subtotal with this price and 24 quantity = $939.60 instead it should be $939.52. I have checked into the database and found that it is calculating with $fprice = 39.15 but I want to calculate with $fPrice = 39.1467 to correct the subtotal value.

Any help would be much appreciated. Thanks.

Database item row :

Answer 1

$items = $this->_cart->getQuote()->getAllItems();
$totalItems = count($items);
if ($totalItems != 0) {
    foreach($items as $item) {
        if($item->getProductId() == $productId){
            $item->setData('qty', $qty);
            $item->addOption(array(
                   'code' => 'additional_options',
                   'value' => $this->_serialize->serialize($additionalOptions)
            ));
            $item->setCustomPrice($fPrice);
            $item->setOriginalCustomPrice($fPrice);
            $item->save();
        }
    }
}

Note: The price and qty will be set in all products cart, you need to get the values dynamically for all products.