"random times" huuum, nope, never lol. It was always an important timeline, basically, they always annunce sales of every 10 million milestone, and sales by the end of the year, that's how this work.
they are not gonna wait for a random 85 million milestone in a random period of the year, if they have not annunced the 80 million milestone then PS4 simply hasn't reach that yet.
They probably have already passed the 80M mark by now - they just have no interest in announcing it anymore. Unless you’re saying that PS4 sales have dropped off a cliff compared to last year.