Still better then FedEx, who weighs every single package, and usually always finds a way to tack on an extra fee, for about a thousand different reasons (fuel surcharge, residential, address look-up, etc...) The one I've seen that really annoys me is "change of address", and you look it up and find out they changed "Apt# 25" to "Suite# 25" or visa versa....and CHARGE your account extra for it.
At least they sent them right back to you from the originating Post Office, instead of waiting until they got to the delivery Post Office and slapped a Postage Due on it, because an over-zealous inspector doesn't realize a 1st Class rigid, flat package, qualifies for Delivery Tracking and doesn't need to be upgraded to Priority Mail.