CTR also depends upon ad position so relative values may again be important.
Well anyway, if you did get a high CTR, there is no guarantee that your CPC will drop fast. QS depends upon may factors and CTR is only one of them.
I find my EPC drops over time slowly, a few cents at a time. It may also depend upon your budget, spending and immediate ad history.
Best way to go about decreasing CPC is working on your Landing page quality , IMHO. I have seen good results as I add outgoing links to my pages and link to a Privacy policy and contact details.
I suggest, increase relevancy to improve CPC. CTR can go up only that much.
Merry X Mas.
Slowly that is for sure, as a percentage of the bid. I have sat there and watched us lose 0000s in a day waiting for the price to drop, and eventually it does, but it can be painfully slow, sometimes tens of thousands of impressions later, so you should factor this into your budgets. I can't put a time on it, but slowly if that helps. We do consider it an investment though, and CPC does fall over time if you maintain the same bids.
We got a great CTR on a reasonably high volume kw the other day, entered the blue space and expected the CPC to fall. So far (20k impressions) it hasn't moved at all. Nonetheless, we are certainly happy because we can now get more volume.
Hope that helps!
Funny, I was talking to a friend last night that basically couldn't keep his ad OFF the top blue spot. He said no matter ho much he dropped the bid, it just kept sticking there, and it was relatively competitive too, maybe sometimes people just don't want that top spot?