In the AdWords space, Google has decided to move the Reach and Frequency report out from the Dimensions tab and over to the Campaigns tab.
By looking at the Customize columns drop down from the Campaigns tab, you’ll see “Reach Metrics” as an option. This lets the user see the unique cookies reached and the average number of impressions reached per cookie for any Display campaign.
Now, you can see those metrics for any variety of time span instead of being restricted to a specific time span, such as by day, week, or month, by simply adjusting the date range after adding the columns to your Campaigns reporting.
It would be a wise to update any scripts, filters or macros that uses this data from the Dimensions tab. The report will stop being available from the Dimensions tab at the start of January 28th.