The Hoefle Telegram for example just has the letter "T". Assuming it proves the number of arrivals at the exact camp we all know as TII would be a disastrous mistake if that turned out to be an error in interpretation (and I believe it is). If 800,000 Jews never arrived at TII, then it is impossible to prove what they did when they got to TII and where they went after. This is something that must be questioned and not taken for granted.
As you mentioned, and as the ROOH post mentions, TII was not documented as the final destination of the transports. There is in fact no documentation indicating that TII was the final destination and the circumstantial evidence, like the transit time from Malkinia, all but proves that the precise location we all know as TII was not the final destination indicated in those documents.
A couple more ideas were brought up on the subject of how this new information might fit into an understanding of TII. First, that TII may have primarily been a Judenlager to keep Jews separate from TI prisoners. As for any "extermination" to have occurred there, there would, of course, be those who were too elderly and/or ill to be able to work at any of the labor camps along the train route (or to be sent further east). It is suggested that these are the Jews (or others) who would most likely have been sent to TII, for euthanasia as part of Aktion 14f13... this could also explain why former T-4 staff were sent here as well.
To me, this is the easiest part of the riddle. To understand, first you have to be aware that Aktion Reinhardt was not named after Reinhard Heydrich, it was named after the State Secretary of the Ministry of Finance Fritz Reinhardt. It was an economic operation for the utilization of property confiscated from Jewish deportees and from the Jewish ghettos during their liquidation. SSPF Lublin under Globocnik was tasked with the responsibility for collecting property, sorting property, destroying useless property, and disinfesting all property acquired throughout the evacuation of the Jews in the General Government.
During the Pohl trial, many WVHA officials testified to this fact- that Aktion Reinhardt was an economic operation for the utilization of confiscated Jewish property which fell under the jurisdiction of SSPF Lublin in the General Government. It was the task of Einsatz Reinhardt to ultimately ship the property back to Germany, WVHA headquarters, where the valuables were stored in the Reichsbank.
How does this relate to TII? Consider this portion of Hoess's statement on Globocnick's operation:
"There were no difficulties for him. He dismissed objections with a wave of his hand. He wanted to destroy the Jews in these areas immediately on the spot, as far as he did not need them for the work on 'his' police bases. He wanted to round up their property in large collection camps and evaluate them for the SS."
There is in fact an enormous amount of evidence that TII served this function. There is documentary evidence, there is substantial archaeological evidence of property buried in the ground at TII. Caroline Sturdy Colls did not find any bodies at TII but she did find a lot of buried property.
It is clear to me that TII was one of these "large collection camps" dedicated to Globocnik's economic task in the General Government. Under this interpretation, the transports could drop off passengers along the way, but keep their luggage until the last stop. All the luggage would then be collected and transported on a smaller train to TII. This camp also would have received property left behind in the liquidated ghettos throughout the Warsaw district.
This would also make TII a counterpart to a very similar secret Jewish collection camp in the Warthageu called the Pabianince Sorting Camp: http://holocaustcontroversies.blogspot. ... erman.html This was another top-secret Jewish camp where property from deportees and the liquidated ghettos was collected and sorted.
I have a post here in AHF where I compare the images from the Pabianince Sorting Camp to the testimony of workers from Belzec, Sobibor, and Treblinka II: https://forum.axishistory.com/viewtopic ... 3#p2334083
To me, that analysis proves that the core functionality of TII was to, in the Warsaw District of the General Government, serve the exact same function as the Jewish Pabianince Sorting Camp in the Warthageu.
Thus, we do not need to assume that 700,000 Jews or more ever step foot in TII. That is almost certainly not true, and this camp had a clear purpose which is accounted for.