Just a weird observation I have made. If I remove my published code here my impressions go down slightly but the CTR and CPM go way up. Total earnings go up also. I have tried it on different days of the week, and the results for me are consistent. I make more money with no publisher code/revenue on DP.
If you have ads on site that do not perform they drag down your earnings. I take ads off any site that does not make me good money and replace them with products related to the topic.