I have a legacy campaign targeting android devices that is having a good performance. One of my top keywords, have a 10 QS, ad relevance average, CTR 20% above average. No competition or very low in my niche.
I started this keyword with a CPC MAX of 0.40, the first days my CPC was 0.15 - 0.10, actually, after 30.000 IMP, the CPC is 0.06 and established. The avg of clicks per day is 600 with a 28% of conversion rate.
I would like to reduce more my CPC, the estimated top page bid is €0.03, so I think that I can reduce my actual CPC an other 50%.
In order to do that I started reducing my CPC MAX to 0.17 and automatically adwords showed me this warning:
Your keyword isn't triggering ads to appear on Google right now due to a low Ad Rank. Ads are ranked based on your bid and Quality Score.
I checked with ad Preview and the keyword didn't showed ads. BTW, After three days with this warning my CPC have reduced to 0.04 - 0.05 and I'm getting clicks and IMP like before.
My question is: why I'm getting this warning if my ads are shown? Why ad preview doesn't show ads to me but yes to the users?
If I have no competition is a good idea to reduce the cpc max in order to reduce the cpc? Why adwords don't bid the minium estimated top page bid?
How Google calculate the CPC is there aren't other advertises? Actual CPC = (AdRank to hit?/Quality Score of Advertiser) + $.01
There are a lot of questions, thank you in advance.