Update: If the site below is to be believed, apparently the AE flights ended on Oct 26, to start again on Apr 02, and the GE flights ended on Oct 13, no start date published yet. @:-)
http://flyteam.jp/airline_route/isg_tpe/flight_schedule
Although these other pages on the same site imply they're still flying?!
http://flyteam.jp/flightnumber/AE7335
http://flyteam.jp/flightnumber/GE685
Either way, since I'm looking at Apr/May, I'd still like to find those prices.