The Keil and Delitzsch commentary is outdated on this matter. The K&D author, writing in the nineteenth century, was incorrect in implying that it was only after the Babylonian captivity that the civil year began in Tishri. In the 20th century, both Valerius Coucke and Edwin Thiele demonstrated that, based on the historical books of the Hebrew Bible, the southern kingdom of Judah always began the official government year in Tishri. See the relevant demonstration in Thiele, Mysterious Numbers of the Hebrew Kings, 3rd ed., pp. 51–53.
In the above citation from K&D, Hitzig was basically on the right track in allowing for the possibility that Ezekiel 40:1 refers to a Jubilee year, except that the BC year was 574 BC, not Hitzig’s 575. See the discussion regarding the correct year in my article “Ezekiel’s Jubilee, Part 1,” pp. 477–79, available online at rcyoung.org/articles/EzekPart1.pdf. The article examines each of the five time-phrases found in Ezekiel 40:1, showing that all are consistent with, and definitely imply, that Ezekiel saw his vision at the beginning of a Jubilee year. The verse, in the original Hebrew, says it was Rosh Hashanah (always a definite day in rabbinic writing, never a vague “beginning of the year” as found in modern mistranslations of this verse), and also the tenth of the month. It was only in a Jubilee year that Rosh Hashanah was on the same day as Yom Kippur, as stated explicitly in Leviticus 25:8–10. In the Babylonian Talmud, tractate ‘Arakhin 12a, the author thought it was so obvious that the Hebrew text of Ezekiel 40:1 necessarily implied that Ezekiel’s vision was dated to the beginning of a Jubilee year that he wrote: “Is it not written ‘In the twenty-fifth year of our captivity, on Rosh HaShanah, on the tenth of the month, in year fourteen after the smiting of the city’? But which year is it when Rosh HaShanah is on the tenth of the month? It must be said that this is a Jubilee.” In other words, he thought that anyone who understood Hebrew should know that this verse necessarily refers to the beginning of a Jubilee year. Then, on the next page of the folio, (‘Arak. 12b), he writes that this was the 17th Jubilee. My article explains that the statement that Ezekiel’s Jubilee was the 17th could not have come from the rabbis somehow calculating the years since the entry into the land, because the chronological methods of the rabbis are, even to the present day, derived from the erroneous chronological methods of the second century AD Seder ‘Olam. The only alternative is that this is a valid historical remembrance.
I have treated this theme—namely that Ezekiel’s Jubilee agrees exactly with the date of the Exodus derived from 1 Kgs 6:1 and the subsequent 40 years in the wilderness—quite extensively since my original publication on the matter in 2003. My nine published articles on this matter are available on my Web site at www.rcyoung.org/User Guide#Jubilee. This reasoning has been accepted by conservative authors including Andrew Steinmann (From Abraham to Paul: A Biblical Chronology, 2nd edition, pp. 39-43) and Scott Stripling (Five Views of the Exodus, pp. 31, 77–78). There has never been an adequate response to this reasoning from biblical skeptics. In Five Views, we only see some poorly reasoned arguments by one of the respondents on page 68; the other three authors, all of whom do not believe in a 15th-century exodus, find it easier to ignore what seems to me a mathematical demonstration that we can trust the Bible in its chronological statements.
In the more than 22 years since my first publication on this matter (“When Did Solomon Die?”), I have never seen an adequate response from biblical skeptics regarding the “coincidence” that the date of the Exodus as derived from 1 Kgs 6:1 is in exact agreement with Ezekiel seeing the vision of the last nine chapters of his book at the beginning of a Jubilee year. The trouble for all those skeptical of the Bible as a valid historical document is that, if this is the case, it means that the book of Leviticus—at least the verses that chart the Jubilee and Sabbatical years—must have been existence in 1406 BC, since there is quite universal acceptance, by both conservative and skeptical scholars, that the Jubilee and Sabbatical years have their origin in the 25th chapter of Leviticus. And a 1406 date for the final chapters of Leviticus necessarily implies Mosaic authorship. It is this idea, which of course our Lord Jesus believed, that skeptical scholarship must avoid at all costs—otherwise they would have to stop being skeptical! For such critics, the easiest course is just not to read, and definitely not to address meaningfully, what conservative scholarship has written on this matter.