[Résolut] EcoTaxe

$sum += $p->$value;
en:
$sum += $p->$value*$p->cart_product_quantity;
dans le fichier principal du plugin.

<?php
/**
 *
 */
class plgHikashopGlobal_cart_fee extends hikashopPlugin {
	var $multiple = true;
	var $name = 'global_cart_fee';

	var $pluginConfig = array(
		'name' => array('HIKA_NAME', 'input'),
		'price' => array('PRICE', 'input'),		//if value has a custom field name, you can enter here either + or - to indicate whether the calculated sum should be shown for information purpose only or add itself to the total
		'value' => array('VALUE', 'input'),		//can be the name of a custom field and in that case the system will sum the values of that field
	);


	function onAfterCartProductsLoad(&$cart) {
		$plugins = array();
		$this->listPlugins($this->name, $plugins, false, true);

		if(!count($plugins)){
			return;
		}

		foreach($plugins as $plugin){
			$this->pluginParams($plugin);

			if(isset($cart->additional['global_cart_fee_'.$plugin]))
				continue;

			$additional = new stdClass();
			if(!empty($this->plugin_params->name)){
				$key = strtoupper($this->plugin_params->name);
				if(JText::_($key)!=$key){
					$this->plugin_params->name = JText::_($key);
				}
			}
			$additional->name = $this->plugin_params->name;
			$value = $this->plugin_params->value;

			$firstProduct = reset($cart->products);
			if(isset($firstProduct->$value)){
				$sum = 0;
				foreach($cart->products as $p){
					$sum += $p->$value*$p->cart_product_quantity;
				}
				if($this->plugin_params->price != '+'){
					$currencyHelper = hikashop_get('class.currency');
					$additional->value = $currencyHelper->format($sum,hikashop_getCurrency());
				}else{
					$additional->price_currency_id = hikashop_getCurrency();
					$additional->price_value = $sum;
					$additional->price_value_with_tax = $sum;
				}

			}else{
				$additional->value = $value;
				if(!empty($this->plugin_params->price)){
					$additional->price_currency_id = hikashop_getCurrency();
					$additional->price_value = $this->plugin_params->price;
					$additional->price_value_with_tax = $this->plugin_params->price;
				}else{
					$additional->price_currency_id = 0;
					$additional->price_value = 0;
					$additional->price_value_with_tax = 0;
				}
			}

			$cart->additional['global_cart_fee_'.$plugin] = $additional;
		}
	}
}

<?php
/**
 *
 */
class plgHikashopGlobal_cart_fee extends hikashopPlugin {
	var $multiple = true;
	var $name = 'global_cart_fee';

	var $pluginConfig = array(
		'name' => array('HIKA_NAME', 'input'),
		'price' => array('PRICE', 'input'),		//if value has a custom field name, you can enter here either + or - to indicate whether the calculated sum should be shown for information purpose only or add itself to the total
		'value' => array('VALUE', 'input'),		//can be the name of a custom field and in that case the system will sum the values of that field
	);


	function onAfterCartProductsLoad(&$cart) {
		$plugins = array();
		$this->listPlugins($this->name, $plugins, false, true);

		if(!count($plugins)){
			return;
		}

		foreach($plugins as $plugin){
			$this->pluginParams($plugin);

			if(isset($cart->additional['global_cart_fee_'.$plugin]))
				continue;

			$additional = new stdClass();
			if(!empty($this->plugin_params->name)){
				$key = strtoupper($this->plugin_params->name);
				if(JText::_($key)!=$key){
					$this->plugin_params->name = JText::_($key);
				}
			}
			$additional->name = $this->plugin_params->name;
			$value = $this->plugin_params->value;

			$sum = 0;
			foreach($cart->products as $p){
				$sum += $p->$value;
			}
			if($this->plugin_params->price != '+'){
				$currencyHelper = hikashop_get('class.currency');
				$additional->value = $currencyHelper->format($sum,hikashop_getCurrency());
			}else{
				$additional->price_currency_id = hikashop_getCurrency();
				$additional->price_value = $sum;
				$additional->price_value_with_tax = $sum;
			}

			$cart->additional['global_cart_fee_'.$plugin] = $additional;
		}
	}
}