well, noticed that there are still many themes in the pack that present a problem with supporter ads insertion, specially in archive/tag pages.
exemple : http://conseilmarketing.mgr-artagency.com/tag/plurimedia/ (this is a splog but kept it for illustration purpose)
Did you take that in consideration for S3 ?? This is really a mess that means very few themes can support ads insertion by supporter.
As told before, this is specific to supporter, since Ads Inserter works just fine.