Via Search Engine Roundtable Forums, PPC Blog UK wrote that Google may be testing something called "Predictive Average CPC" in the up coming months.
He tries to explain;
The theory behind this is that it will provide advertisers with much greater control over the actual cpc they pay for a keyword rather trying to control the average bid through the max cpc you are prepared to pay to.
Honestly, I still do not 100% understand this.
It is to work as an alternative (you choose) for the Max CPC bid option.
Forum discussion at Search Engine Roundtable Forums.