Update product price from custom fields value

Hi,

i need to update the product price based on values from some custom fields

this is how i’ve build and saving the custom fields, at the end i’m trying to update _regular_price based on the values of the customs fields when i save, update, publish the product but nothing is happening, what am i missing?

/BUILD AND SAVE FIELDS
//meta
// Display Fields
add_action( 'woocommerce_product_options_general_product_data', 'woo_add_custom_general_fields' );

function woo_add_custom_general_fields() {

  global $woocommerce, $post;
  
  echo '<div class="options_group">';
  
// Product URL
woocommerce_wp_checkbox( 
array( 
	'label'	=> __('Product URL', 'woocommerce' ), 
	$post_id = $_GET['post'],
	$produrl = get_post_meta( $post_id, 'productOriginalUrl', true),
	'description'   => '<a href="' . $produrl . '" class="button button-primary button-large" target="_blank">' . __('View Product', 'woocommerce') . '</a>',
	)
);
	
	// Number Field
woocommerce_wp_text_input( 
	array( 
		'id'                => '_price_usd', 
		'label'             => __( 'Price in USD', 'woocommerce' ), 
		'placeholder'       => '', 
		'description'       => __( 'Enter the custom value here.', 'woocommerce' ),
		'type'              => 'number', 
		'custom_attributes' => array(
				'step' 	=> 'any',
				'min'	=> '0'
			) 
	)
);
woocommerce_wp_text_input( 
	array( 
		'id'                => '_price_tax', 
		'label'             => __( 'TAX', 'woocommerce' ), 
		'placeholder'       => '', 
		'description'       => __( 'Enter the custom value here.', 'woocommerce' ),
		'type'              => 'number', 
		'custom_attributes' => array(
				'step' 	=> 'any',
				'min'	=> '0'
			) 
	)

);
woocommerce_wp_text_input( 
	array( 
		'id'                => '_price_shipping', 
		'label'             => __( 'Shipping', 'woocommerce' ), 
		'placeholder'       => '', 
		'description'       => __( 'Enter the custom value here.', 'woocommerce' ),
		'type'              => 'number', 
		'custom_attributes' => array(
				'step' 	=> 'any',
				'min'	=> '0'
			) 
	)

);

// Select
woocommerce_wp_select( 
array( 
	'id'      => '_shipping_weight', 
	'label'   => __( 'Shipping Weight', 'woocommerce' ), 
	'options' => array(
		'3.75'   => __( 'Less Than 0.5 KG', 'woocommerce' ),
		'7.5'   => __( '0.5 KG', 'woocommerce' ),
		'15' => __( '1 KG', 'woocommerce' )
		)
	)
);

// Hidden field
woocommerce_wp_hidden_input(
array( 
	'id'    => '_usd_rate', 
	'value' => '18'
	)
);
	echo '</div>';
};

// Save Fields
add_action( 'woocommerce_process_product_meta', 'woo_add_custom_general_fields_save' );
function woo_add_custom_general_fields_save( $post_id ){
		
	// Number Field
	$woo_price_usd = $_POST['_price_usd'];
	if( !empty( $woo_price_usd ) )
		update_post_meta( $post_id, '_price_usd', esc_attr( $woo_price_usd ) );
	
	$woo_price_tax = $_POST['_price_tax'];
	if( !empty( $woo_price_tax ) )
		update_post_meta( $post_id, '_price_tax', esc_attr( $woo_price_tax ) );
	
	$woo_price_shipping = $_POST['_price_shipping'];
	if( !empty( $woo_price_shipping ) )
		update_post_meta( $post_id, '_price_shipping', esc_attr( $woo_price_shipping ) );
	
	// Select
	$woo_shipping_weight = $_POST['_shipping_weight'];
	if( !empty( $woo_shipping_weight ) )
		update_post_meta( $post_id, '_shipping_weight', esc_attr( $woo_shipping_weight ) );
		
	// Hidden Field
	$woo_usd_rate = $_POST['_usd_rate'];
	if( !empty( $woo_usd_rate ) )
		update_post_meta( $post_id, '_usd_rate', esc_attr( $woo_usd_rate ) );
		
}

//UPDATE PRICE REGULAR
function wpa104760_default_price( $post_id, $post ) {
		

    if ( isset( $_POST['_regular_price'] )) {
$post_id = $_GET['post'];
		$woo_price_usd = get_post_meta($post_id, '_price_usd', true);
		$woo_price_tax = get_post_meta($post_id, '_price_tax', true);
		$woo_price_shipping = get_post_meta($post_id, '_price_shipping', true);
		$woo_shipping_weight = get_post_meta($post_id, '_shipping_weight', true);
		$woo_usd_rate = get_post_meta($post_id, '_usd_rate', true);
		
$woo_new_product_price = (($woo_price_usd + (($woo_price_usd*$woo_price_tax)/100) + $woo_price_shipping + $woo_shipping_weight) * $woo_usd_rate );
		
update_post_meta( $post_id, '_regular_price', $woo_new_product_price );
	    }

}
add_action( 'woocommerce_process_product_meta', 'wpa104760_default_price' );