Questions Answered - And Asked, about Dual Native ISO

I just wrote about some niche issues that got answers from Blackmagic, as I hadn't seen the topics discussed elsewhere amidst bloggers reciting no more than basic specs:

http://www.focuspulling.com/bmpcc4k-learning/

Yet honing in to the issue of Dual Native ISO, something in the manual seems rather peculiar (and at odds with what I was verbally told by Blackmagic (though of course in the rush of conversations, numbers understandably can get scrambled). The official manual implies that 1250 ISO actually activates the native ISO of 3200 (advising that once we get to the range of 1000 ISO, it's better to bump up to 1250 ISO).

I want to make sure that this isn't a mistake in the manual, as it seems/feels counter-intuitive for obvious reasons (and I was advised to bump up to 3200 ISO upon reaching the ceiling of the lower half range just below it). What do you think?

Thanks,
Paul
https://twitter.com/BMCCusers/ & https://www.facebook.com/BMCCusers/

Several demos of this have been posted, rhe csmera nosie jumps down at ISO1200, and the image looks much better compared to iOS 1000. 1200 seems the bottom of the 3200 range, just as 200 is the bottom of the 400 lower iso range.