They were released at 6:15am when I bought my tickets this past summer. Fares did go up on my flights immediately after I completed my purchase. So, there is some benefit to purchasing as soon as they are released.
I've been watching the rates since then & they have been fluctuating (other flights the same days, not the ones I purchased, they've stayed the same). This week they released a sale that did reduce the price of other flights on the same days, but not my flights.
So, it's really a crap shoot, but for me, there was definitely a benefit to purchasing as soon as they were released (at this point).