It has never had multiple sale items feature as far as I know. In beta they had it once but they disabled it there too! Uhh. It sure is a pain to sell multiple stacked items one-by-one all the time. :/ It´s so time consuming.
And actually, from the Beta forums topic, darkguardian666 made it sound like selling for below the minimum wasn't the only issue with it, but it also wasn't intended for selling in lots, just creating multiple postings at once, so it wouldn't even be any more convenient for buyers. I might be wrong though, it's been a while since I've read it.