The wording from "These Are the Voyages" doesn't suggest that Algeron would have predated Tomed, and been revised at that time. Rather, the revision that happened in the early 24th century was called the Treaty of Algeron, putting it apart from any preceding treaties. Otherwise Troi wouldn't immediately associate the treaty of that name with the year 2311 and the redefining of the Neutral Zone.
We don't know if there's a relationship between Tomed and cloaking as such. Or between Tomed and the year 2311, or between Tomed and the Treaty of Algeron. Heck, the only time the Tomed Incident is mentioned in Star Trek at all, in TNG "The Neutral Zone", it is left undefined save for one thing: after that but before the episode, there had been no "direct contact" with the Romulans. For all we know, Tomed was unrelated to Romulans, too, and merely a convenient historical event coinciding with the loss of Romulan contact - similar to somebody saying "there hasn't been plague in Europe since the Reformation" without implying in the slightest that Martin Luther had anything to do with ending the plague.
Timo Saloniemi