Well, I hate to correct you, but right now AS is not
For example Bonanza.....A very old show (so not even close to HD), however also not as crappy as the stream AS picks.
AS defaults the download to 576x432 while a "high resolution" of 640x480 is available when you check the available downloads.
It seems AS remembers the setting AFTER the download for each show, but sometimes picks "random" resolutions for the initial download if its under 1080 .
Trying Knight Rider, same thing....first attempt the crappier resolution preselected.
Note: Any show/movie available in 1080, AS correctly picks the 1080 stream