Snippet to support CodeCanyon WooCommerce Currency Switcher. Note - In Plugin Settings Currency should be set to the fedex account country. No need of Conversion rate. WooCommerce FedEx Shipping Plugin with Print Label - https://www.pluginhive.com/product/woocommerce-fedex-shipping-plugin-with-print-label/

functions.php

/**
 * Snippet to support CodeCanyon WooCommerce Currency Switcher. Note - In Plugin Settings Currency should be set to the fedex account country. No need of Conversion rate.
 * Created at : 01 Dec 2018
 * Updated at : 01 Dec 2018
 * PluginHive Plugins : https://www.pluginhive.com/plugins/
 * Gist Link : https://gist.github.com/varun-pluginhive/314791bd8f864075e43b857feb1e0c72
 */

// Rate Request
add_filter( 'xa_fedex_rate_request', function( $request ){
	$fedex_base_currency = 'MXN';		// Currency supported by Woocommerce
	$fedex_currency = "NMP";			// Currency Supported by Fedex

	if( class_exists('WOOCS') ) {
		$woocs 					= new WOOCS();
		$currencies 			= $woocs->get_currencies();
		$current_currency 		= get_woocommerce_currency();
		$fedex_settings 		= get_option( 'woocommerce_'.WF_Fedex_ID.'_settings', array() );
		$currency_in_request	= $request['RequestedShipment']['PreferredCurrency'];
		if( ! empty($currencies) && ! empty($current_currency) && ! empty($currencies[$current_currency]['rate']) ) {
			$exchange_rate_to_default 	= (double) $currencies[$current_currency]['rate'];
			$exchange_rate_to_fedex		= ! empty($currencies[$fedex_base_currency]['rate']) ? (double) $currencies[$fedex_base_currency]['rate'] : 1;
			$request['RequestedShipment']['PreferredCurrency'] = $fedex_currency;

			// Replace Insured amount
			foreach( $request['RequestedShipment']['RequestedPackageLineItems'] as &$line_items ) {
				if( ! empty($line_items['InsuredValue']) ) {
					// $line_items['InsuredValue']['Currency'] = $fedex_currency;
					$line_items['InsuredValue']['Amount']	= ( ( (double) $line_items['InsuredValue']['Amount']) / $exchange_rate_to_default ) * $exchange_rate_to_fedex;
				}
			}

			// Replace Total Insured Value
			if( ! empty($request['RequestedShipment']['TotalInsuredValue']) ) {
				// $request['RequestedShipment']['TotalInsuredValue']['Currency'] = $fedex_currency;
				$request['RequestedShipment']['TotalInsuredValue']['Amount']	= ( ( (double) $request['RequestedShipment']['TotalInsuredValue']['Amount']) / $exchange_rate_to_default ) * $exchange_rate_to_fedex;
			}

			// Replace Commoditeies Unit price and Custom Value
			if( ! empty($request['RequestedShipment']['CustomsClearanceDetail']['Commodities']) ) {
				foreach( $request['RequestedShipment']['CustomsClearanceDetail']['Commodities'] as &$commodities ) {
					// Convert UnitPrice
					if( ! empty($commodities['UnitPrice']['Amount']) ) {
						$commodities['UnitPrice']['Amount'] = ( ( (double) $commodities['UnitPrice']['Amount']) / $exchange_rate_to_default ) * $exchange_rate_to_fedex;
					}
					// Convert Customs Value
					if( ! empty($commodities['CustomsValue']['Amount']) ) {
						$commodities['CustomsValue']['Amount'] = ( ( (double) $commodities['CustomsValue']['Amount']) / $exchange_rate_to_default ) * $exchange_rate_to_fedex;
					}
				}
			}

			//Convert Total Custom Value
			if( ! empty($request['RequestedShipment']['CustomsClearanceDetail']['CustomsValue']) ) {
				$request['RequestedShipment']['CustomsClearanceDetail']['CustomsValue']['Amount'] = ( ( (double) $request['RequestedShipment']['CustomsClearanceDetail']['CustomsValue']['Amount']) / $exchange_rate_to_default ) * $exchange_rate_to_fedex;
			}
		}
	}
	return $request;
});

// Label Request

if( ! function_exists('ph_fedex_shipment_rate_conversion_request') ) {
	function ph_fedex_shipment_rate_conversion_request( $request, $order ) {
		$fedex_base_currency = 'MXN';		// Currency supported by Woocommerce
		$fedex_currency = "NMP";			// Currency Supported by Fedex

		$order_base_currency 	= $order->get_meta('_woocs_order_base_currency');
		$order_conversion_rate 	= (double) $order->get_meta('_woocs_order_rate');
		if( class_exists('WOOCS') ) {
			$woocs 					= new WOOCS();
			$currencies 			= $woocs->get_currencies();
			$exchange_rate_to_fedex = ! empty($currencies[$fedex_base_currency]['rate']) ? (double) $currencies[$fedex_base_currency]['rate'] : 1;
			
			if( ! empty($currencies[$fedex_base_currency]['rate']) ) {
				// Cost Conversion For Insurance Value
				foreach($request['RequestedShipment']['RequestedPackageLineItems'] as &$line_items ) {
					if( ! empty($line_items['InsuredValue']) ) {
						$line_items['InsuredValue']['Amount'] = (double) $line_items['InsuredValue']['Amount'] * $exchange_rate_to_fedex;
					}
				}

				// Amount COnversion for TotalInsured Value
				if( ! empty($request['RequestedShipment']['TotalInsuredValue']) ) {
					$request['RequestedShipment']['TotalInsuredValue']['Amount'] = (double) $request['RequestedShipment']['TotalInsuredValue']['Amount'] * $exchange_rate_to_fedex;
				}
				// Cost Conversion for Custom Vale
				if( ! empty($request['RequestedShipment']['CustomsClearanceDetail']) ) {
					$request['RequestedShipment']['CustomsClearanceDetail']['CustomsValue']['Amount'] = ( (double) $request['RequestedShipment']['CustomsClearanceDetail']['CustomsValue']['Amount'] / $order_conversion_rate) * $exchange_rate_to_fedex;
				}

				// Cost Conversion for Commodities
				foreach( $request['RequestedShipment']['CustomsClearanceDetail']['Commodities'] as &$commodities ) {
					$commodities['UnitPrice']['Amount'] 	= (double) $commodities['UnitPrice']['Amount'] * $exchange_rate_to_fedex;
					$commodities['CustomsValue']['Amount'] 	= (double) $commodities['CustomsValue']['Amount'] * $exchange_rate_to_fedex;
				}
			}
		}
		return $request;
	}
	add_filter( 'wf_fedex_request', 'ph_fedex_shipment_rate_conversion_request', 10, 2 );
}