From 2366 until 3339 - the year of the first Churban - is a Moed, 973 years, 69.5 "weeks" of fourteen years each. From 3339 until 3829 - the year of the second Churban - is half a Moed, 70 "weeks" of seven years. From 3829 until 5775 is the period of Moadim, 69.5 "weeks" of 28 years, the length of the Machzor Gadol. The second Churban was in year ת of the 15th Machzor Gadol. The additional 69.5 "weeks" bring us to year ז of the 85th Machzor.
Daniel 9:27 says about the last of the 70 weeks: "He will forge a strong covenant with the great ones for a week, and at half a week he will abolish sacrifice and meal-offering." This is what happened to Bayit Rishon, after 69.5 weeks of its Moed.
Daniel 9:26 says that after 62 weeks a Moshiach is cut off. King Chizkiyah died (it seems) in 3230, at 61.71 "weeks."
We saw earlier that the first Churban came one Shmita period before the end of Yovel 36, and that the first Shmita of Yovel 85 comes to complete Yovel 36. From the present point of view, then, we see that it comes to complete the Moed of Bayit Rishon and makes it into 70 whole "weeks" of fourteen years.
In this light, I venture to say the following. After the Moadim's 69.5 weeks of 28 years, the Jewish sacrifices at the Altar of the Exile will stop. I note that the Vilna Gaon died in 5558, at 61.75 "weeks."
The first Shmita of Yovel 85 culminates in year eight of the Yovel, year Samech of Mazchor 85, which represents Yovel year 36. After this year, the 70 "weeks" of the Moadim are completed. Thirteen years remain until the Tikkun of the third Aleph Sofit at the end of the Machzor. This leaves one year for the completion of the Moadim. That year is the year of the third Samech. See this post and its references.
[Update: As pointed out in the comments, during Bayit Sheni, Hillel died in 3771, at 61.71 "weeks." At 69.5, Eliezer ben Hananiah stopped the sacrifices for the Emperor of Rome.]
Sanhedrin 97b brings:
אמר ליה אליהו לרב יהודה אחוה דרב סלא חסידא: אין העולם פחות משמונים וחמשה יובלות, וביובל האחרון בן דוד בא. אמר ליה: בתחילתו או בסופו? אמר ליה: איני יודע. כלה או אינו כלה? - אמר ליה: איני יודע
Eliyahu said to Rav Yehuda, the brother of Rav Sala Chasida: The world does not last less than 85 Yovel periods, and in the last Yovel period Moshiach comes. [Rav Yehuda] said to him [Eliyahu]: "In the beginning or in the end (of the last Yovel period)?" [Eliyahu] said to him: "I do not know." Will it be completed or not? [Eliyahu] said to him: "I do not know."
I think that the above answers what Eliyahu did not know.
