Woocommerce Extended Coupon Features Pro is a good plugin with really awesome features. But there is one major issue with the plugin. It slows down the checkout process (load time as well as payment processing) by 3-4 seconds when it is used to apply coupon by URL. I have tested this on my site store.pmfias.com. I have tested Woocommerce Url Coupons Plugin and Woocmmerce Smart Coupons plugin as well. They don’t slow down the checkout page. But WECF Pro has a significant impact on checkout load time. If you could rectify this issue then I would say that the plugin is 100% perfect.