Andy_Langton - 10:52 pm on May 1, 2012 (gmt 0)

I'm not an Adwords guy, but this makes no sense to me either. This note on the Adwords page looks like a pain (and totally unhelpful) for those of you managing many campaigns and adgroups:

Note that a campaign’s ‘Ad rotation’ setting will continue to say ‘Rotate evenly’ after the even rotation period has ended for any or all of the ad groups in the campaign.