I found no thread to this bug which I think is really strange and annoying so I started one by myself.
I noticed this bug right after the addon went live and no bugfix yet.
at the moment it is not possible to arrange items in the AH properly from lowest to highest buyout.
when I click on "buyout" (even multiple times) it arranges the items to no logical order. first I thought the AH would arrange it from lowest to highest "high bid" since lots of people started with a "high bid" of 1 so their items would be the first in list but even that is not always happening.
when I first press 1 time on "buyout" and then on "name" it arranges the items from lowest to highest buyout but does not consider the lowest price per item which it was before addon.
example: someone wants to sell one item of "x" for 100 ads and another one wants to sell 10 items of the same kind for 900. so I press like I explained first "buyout" and then "name" to arrange them.
before addon the 10 items used to be arranged before the 1 item (from low to high price) because per item the 10 are cheaper since the price is per item only 90 but the AH house arranges the one item before the 10 because 100 is smaller than 900 which is really impractical in my opinion.
I hope for some response and that you change the system to the system it was before the addon went live.
I can confirm that the sorting by "Buyout" doesn't work properly and it doesn't sort in a crescent/decrescent way.
I can also add that also the filters in the "Search" function don't work properly.
You can use some filters like "Power" "Recovery" "Armor Penetration" and it will show you items with "Power" "Recovery" and "Critical Chance"
On the gateway you can list by buyout price but, as the OP says, it no longer sorts by the average price per item but rather by the total price regardless of the stack size.
Comments
I can also add that also the filters in the "Search" function don't work properly.
You can use some filters like "Power" "Recovery" "Armor Penetration" and it will show you items with "Power" "Recovery" and "Critical Chance"
Er, it's also a sticky in General Discussions...
http://nw-forum.perfectworld.com/showthread.php?461231-Known-Issues-Please-look-here-for-updates!&p=5770171&viewfull=1#post5770171