Originally Posted by
WineCountryUA
If the route does not require the pilot rest, the seat will be freed up a bit more the 48 hours out.
Discussion of that in more depth in the reference thread.
UA only has the ER version
Jan 16 / Jan 17 / Jan 18 flights are 767-400 while Jan 19 / Jan 20 flights are 767-400ER. Maybe they are wrong information on United.com