Postage Paid Reply Envelope Cancel Title is required

I really like the idea of CI including a postage paid reply envelope in with the letters that we receive from our kids so that we can mail a reply to the Kansas City office. The wording on the envelopes imply that if I mail out one of the said envelopes from the United Kingdom it will reach the Kansas City office without any further postage needing to be addef. So basically as I understand it, I can simply place my letter inside, seal it and then drop it into an outgoing mail receptacle or drip off at my local post office. Can somebody on here please confirm if I am correct or not before I go ahead and use one of the aforementioned envelopes. 

Yes, if the CI envelope says “International Business Reply/Réponse Payée” and, where the stamp should be, “No postage necessary if mailed to the United States”, then you need not buy stamps or pay for postage. I’ve used them from Belgium and I know CI, and the children, have received my letters.