Reef Crest Random Mode: How Random is Random?

[Kengar]

I'm playing with my new WWD's, checking out the various modes with one master and one slave in anti-synch. As far as I can tell, the master is not doing much changing in reef crest random mode. What sort of changes should I be seeing? Speed ramping up/down? On off? Pulsing? What sort of time period between changes should I be seeing? Seconds? Minutes?