In my case I'm just beating a dead horse, but I guess it's not easy to just forget about it and move on, as I spent many hours on this. I guess it's throwing good money after bad, but...
I'd appreciate people's feedback. Btw, I've never been able to get a non-canned answer from Google. Always very polite, very nice, but only canned answers (either for tech matters e.g. the bug with non-Latin charset adsense ads on content-sites, to this one).
So let's think about EPC.
An indirect PPA is fine for B2C stuff. OK, so 1 out of 50 visitor sent via Adwords, buys ie completes a transaction on the e-commerce site's cart. Fine, the publisher's site gets some bonus, for sending "quality leads".
But what about B2B?
How would one measure conversions on a B2B site? I would say, pages-per-visitor and time-spent-per-visitor, right?
I've visited a sample of about 40 sites of advertisers who got clicked via my pages, and I can't find the conversion code anywhere.
I ran an Adsense monitor script, so I look back at the clicks on my test site, to advertisers: some Adwords advertisers I sent clicks to are small manufacturers and are some big companies, like Bayer pharma or Shell (oil, you know). On subjects like "oil refinery performance tuning". I do some WHOIS investigation of clicker's IP, and sometimes come up in intranets of large companies in the same industry.
Yet, all it ever got was rock-bottom EPC.
And btw I'm talking about pretty good (imo) content, not "phony directory" kind of stuff, DMOZ ripoffs etc etc. Data was compiled & verified independantly, 2200 pages, 400 of them translated in 5 languages (by pro translators).