actual cpcs seem to still be calculated mostly on the CTR,
As I understand it, the ranking of your Ad is dependent on you actual bid and the QS. The Cost Per Click you are actually charged should be the minimum amount necessary to achieve the same ranking for the search concerned.
So the only relationship between CPC and CTR is through the Quality Score. My understanding is that Ad CTR has less impact on the QS than landing page/site quality, ad text relevance, and landing page relevance.
My understanding is that Ad CTR has less impact on the QS than landing page/site quality, ad text relevance, and landing page relevance.
In the case I stated above I would believe CTR (part of QS, according to Google) and its history affected my bids and actual cpc a lot!