When you see a high eCPM, do you do anything as far trying to optimize your page? I'm trying to figure out what eCPM really tells you. Does it mean much in terms of earning more?
When you have a high eCPM it will only you more money when trafic increases. For example: Page A has a eCPM of 10 dollars but 1000 impressions per day. Page B eCPM of 5 dollars but 2000 impressions per day. In this case it would be interesting to find a way to increase trafic to page A as well, given it's high eCPM, although this high number may be the result of a few extra clicks on a certain day, it's better to compare them over the time of a few days to get a more reliable idea, especially when your traffic is quite low.
You can try to optimize it by having less impressions per clicks. You can also have more high paying keywords targeted.