^ Yes, I agree. My original post was on the back of my first couple of runs through the battlefield where it appears that the RNG was being unusually nice to me (I think Bawb may have been logged on at the same time). It has certainly made up for it since

Interesting to note that, even this long after the roll-out of NS-13, the ascots are still floating around the 1M mark suggesting that either the ascot is hard to come by, demand remains high, or that people are optimising the battlefield to reduce turncount and thereby reducing the probability of yielding and ascot.
The above would suggest either one of three mechanics - a percentage chance to appear for each hero; the semi-rare mechanic, or something akin to it is in play; the game randomises for each run how many heroes you will face and on which enemy number the hero will appear.
Personally, my money is on the last one.
Regardless, the battlefield is one of the biggest meat-making areas in the game at the moment.