nRF52832 Advertising Interval

[John]

I've been puzzled after looking at the current draw figures for the nRF52832. If the advertising interval is supposed to be 20ms.

Can someone explain why the advertising event is actually 25ms?

Or why the advertisng is added to the interval?

[John]

The stack is supposed to add a random delay between 0 and 10mS to each advertising interval to help minimize collisions. There is a good explanation of advertising here:

Advertising explained

[RichieJH]

Thanks for the paper John. I'm too lazy to dig deeper and the paper doesn't mention it, but is that randomness set on the first advertisement and doesn't change or is it randomised for each and every advertisement?