Scrying the aethyrs - change at NIA, why? Options

When scrying the aethyrs from TEX to NIA, there seems to be a fairly steady line of developments in which you could almost write a continuous story from it, but it changes when you get to NIA, I have been trying to understand why before I proceed.

Will it only become clear after I proceed?

Does it seem to change a lot for everyone at NIA or does the story change for some people on other aethyrs?

Is it different each time you start the journey from TEX?

Would prefer answers from members who have actually done this rather than mere speculation please.

Arg, can't find my notes...
I have found that some areas in the Aethyres are suddenly really difficult to get past, but cannot remember which offhand. I have not traveled all of the aethyres for about a year now.
For me it seemed as though as I went up they became less dense, and less anthropomorphised as far as the beings I encountered go. I also noted that the visions became more intense and vivid as I got further up, yet harder to put into words.
Whenever I got to one of the 2 or 3 places along the aethyres where I got stuck I would just take a break for a week or 2 then tackle them again when I had integrated everything more. Some people can seem to do the aethyres all in a row, and sometimes all in a sitting, or each day in a row. It never worked that way for me however hard I tried LOL. I sort of went at them as I felt ready, and there were definatly 2 or 3 places I had to take a break.
One trick I used was one that I used with the tree of life. When going up the tree if I find that I am having difficulty ascending, I sort of lose some of my solidity/heaviness as I go up, as well as lose some of my concepts and thoughts as I go further up, so eventually I am a lot less dense and a lot less how I was when I started in malkuth. Hope that made some sense (IMG:style_emoticons/default/smile.gif)

Athena