that's because their user interface sucks. notice that they have TWO stations listed with the abbreviation "NOR." because that makes total sense.
you're probably looking at the north springs schedule, which is why you're seeing the service stop.
this is going to be way too much information, but here we go:
here's the deal: there are two north/south lines. north springs and doraville. the doraville and north springs line are identical right up to lindburgh station, where they split like a Y. get on the right train and you don't have to transfer.
however, after 9:30 trains stop going all the way from the airport to north springs. after 9:30 if you're south of lindburgh and want to head northwest, you have to catch a doraville train and switch at lindburgh center (the very next stop) to transfer to a north springs train. travel on from there.
but basically if you're going to get a hotel around midtown station or north avenue station, you're travelling south and the service switch doesn't affect you one bit. every southbound train coming through that station goes where you want to go, up until around 1:30 a.m.
if you're travelling north after the show, you'll have to hop on a northbound doraville train. then either transfer at lindburgh to head northwest or stay on the doraville train to head northeast.
here's the doraville schedule so you can see what i mean.