I love striking a blow for the Sothic dating system and its enemies—take that! Or this. Before I get to the next indicator that it is correct, I suppose I should outline my 18th Dynasty chronology for the record, starting with Thutmose I. This is not arbitrary and I've obviously put a lot of thought into it.
Thutmose I=begins reign 1520 BCE for 16 years
Thutmose II=begins reign 1504 BCE for 3 years
Thutmose III= begins reign 1501 BCE for nearly 54 years by the official record but gains 3 due to the false count initiated by Hatshepsut during their co-regency. But even if I'm wrong there, it doesn't much matter for the purposes of this post.
Amenhotep II =begins reign in 1450 for 26 years. I do not believe in a co-regency for him and Thutmose III.
Thutmose IV=begins reign in 1424 for 9 years
Amenhotep III=begins reign in 1415 for 38 years
Akhenaten= begins sole reign in 1377 after a 3-year co-regency with Amenhotep III. He rules for 14 more years.
Smenkhkare=begins reign in 1363 for 1 year
Neferneferuaten=begins reign in 1362 for 3 years
Tutankhamun=begins reign in 1359 for 10 years
Ay=begins reign in 1349 for 4 years
Horemheb=begins reign in 1345 for 14 years
Obviously, due to unknown factors, the above cannot be a precise chronology but I'll explain why it's probably close. TT50 belonged to a man named Neferhotep, whose title was God's Father of Amun. There was an inscription in the tomb dated to Year 3 of King Horemheb. An interesting thing about TT50 is that it contained a list of feast days, according to a fragment discussed in a paper by Lise Manniche here:
The fragment supposedly states that the “feast of Termuthis” or Renenutet, goddess of the harvest, took place on Day 1 of the 1st month of Shomu in the time of Horemheb. Of course, later in Egyptian history, the month named after the goddess, called Pharmouti, was the 4th month of Peret, one month earlier. In fact, in the Alexandrian or Coptic Calendar, a reformation of the old Civil Calendar, Pharmouti [or Barmouda] was definitely supposed to fall in the time of harvest. The next month Pakhons [or Bashans] was said by the Egyptians to be the time when the threshing was done. According to my high chronology, Year 22 of Thutmose III was 1482. This pharaoh could not take his army east until after the harvest was completed, as the citizen soldiers were not free until then. Indeed, Thutmose and his force reached Tjaru in order to march into Canaan on Julian April 20th, [25 Pharmuti, 4th month of Winter]. The king obviously did not want to miss the Canaanite wheat harvest, which lagged slightly behind that of Egypt, so he could reap that, as well. [At left, two women from Deir-el Medina worship Renenutet]
However, in the time of Horemheb, 1345 BCE, it was very appropriate to celebrate the feast of Renenutet in the 1st month of Shomu as, in his reign, that was the month the harvest was in full swing! In fact, in 1345, April 15 amounted to 25 Pakhons—on which day in that month the time of reaping and threshing would have been long over in the reign of Thutmose III. Therefore, the feast of Renenutet seems to have been a moveable one—and appropriately moved to the 9th month of the Civil Calendar in the time of Horemheb. That this was the Civil Calendar is further indicated by the same list, in which New Year's Eve falls on Day 30, 4th month of Shomu. At this period, the astronomical new year, which arrived with the heliacal rising of the star, Sothis, was edging very close to the new year of the Civil Calendar and a new Sothic cycle was soon to begin.