Recently I've had two with 88¢ postage arrive at their destination with "Postage Due 34¢" stamped on them. Interestingly enough, the recipients said that the packages were delivered with the postage due stamp BUT no one ever tried to collect the extra postage from them. Just this week I had one returned to me with the postage due stamp. When I took it to the counter to question the postage due, the lady said that it depended on where in the delivery stream the insufficient postage was detected. If it was found in a distribution center it would be returned to the sender. If the carrier detected it the package should be delivered to the recipient and money collected upon delivery. That lady insisted that $1.22 (parcel)postage was required.