saunaking is meaning to do it as semitappes, so not the route being a-b a-b (which as you say would cover same distances as a-b-a) but instead doing the same ITT twice, once in the morning and once in the afternoon, so the distance covered is similar to the original time trial but the security only needs to be the same amount, similar to my suggestion of doing two laps in order to keep the distance but reduce the logistical demand on security.Is doing a-b twice not the same as a-b-a? Which is what they did.
UCI's rules don't allow for semitappes anymore, at least not at the WT level, and they were usually a road stage and an ITT for the most part anyway, but there were occasional exceptions. For example, the Peace Race back in 1971 had a 33km morning ITT from Bischofswerda to Dresden, then a short afternoon cobbled MTT on the Borsberg.