If you are using standard PayPal payment module, and want to use discount coupons, there is some issue that you need to fix. On default setting discount coupons will not work with this payment module.

The customer will see amount deducted on order confirmation page but once moved to chaeck out page PayPal site, the amount is shown without discount.

I have posted solution to this issue on my blog, see the post http://blog.wasimasif.com/paypal-payment-module-discount-coupons-problem-cre-loaded/

For more CRE Loaded related fixes see http://blog.wasimasif.com