It is most concerning to me that PayPal apparently allow merchants to add additional costs to a transaction after it has been authorized. This opens an easy route to fraudulent activity that could go unnoticed by your customers. Recently I purchased an item costing £1.20 from a Vendor using PayPal. When the PayPal confirmation arrived I noticed that transaction amount had increased to over £82 without my explicit authorization. When the order confirmation email subsequently arrived I saw that an additional item had been added to my order that was not referenced in the merchants checkout screens or the PayPal authorization screen. I currently have a case concerning this transaction in your Resolution Center but I would also like this loop hole to be investigated and closed in case it should escape the attention of some other customer.