https://github.com/totaljs/node-paypal-express-checkout/issues/24

Hello @petersirka ,
I have solved issue for shipping charges.

Just added -
params.PAYMENTREQUEST_0_SHIPPINGAMT = data.PAYMENTREQUEST_0_SHIPPINGAMT;
line in Paypal.prototype.getExpressCheckoutDetails method.

Paypal.prototype.getExpressCheckoutDetails = function(token, doPayment, callback) {
	var self = this;
	var params = self.params();

	params.TOKEN = token;
	params.METHOD = 'GetExpressCheckoutDetails';

	self.request(self.url, 'POST', params, function(err, data) {
		if (err) {
			callback(err, data);
			return;
		}

		if (!doPayment) {
			return callback(null, data);
		}
		var params = self.params();
		params.PAYMENTACTION = 'Sale';
		params.PAYERID = data.PAYERID;
		params.TOKEN = token;
		params.PAYMENTREQUEST_0_AMT = data.PAYMENTREQUEST_0_AMT;
		params.PAYMENTREQUEST_0_CURRENCYCODE = data.PAYMENTREQUEST_0_CURRENCYCODE;
		params.PAYMENTREQUEST_0_ITEMAMT = data.PAYMENTREQUEST_0_ITEMAMT;
		params.PAYMENTREQUEST_0_SHIPPINGAMT = data.PAYMENTREQUEST_0_SHIPPINGAMT;
		params.METHOD = 'DoExpressCheckoutPayment';

		self.request(self.url, 'POST', params, function(err, data2) {
			if (err) {
				callback(err, data2);
				return;
			}

			if (data.ACK  !== 'Success') {
				return callback(new Error('Error DoExpressCheckoutPayment'), data2);
			}


			// Combine results of getExpressCheckout and DoExpress checkout payment.
			callback(null, _.extend(data, data2));
		});
	});

	return self;
};