CPC's can change significantly in a short amount of time. CPC prices are set by competition among advertisers. If the number of advertisers drop for certain keywords, then the cpc will also drop. The number of advertisers is dependent on their ad budget and whether they feel they are getting their money's worth with CPC. Use to do a lot of CPC at one time, just wasn't worth it for me and quit all CPC ads.
Anyway, what I meant to say was, the $10.47 may be old information