Impressions halved in "search keywords" vs "search terms"?

[Mark_A]

I select an ad group, last 30 days, keywords, select search keywords and note clicks & Impressions.

Without changing anything, I click search terms, and though clicks are the same, impressions are much reduced.

AdWords Beta

Impressions should be the same viewed for search keywords or search terms!

Anyone know what is going on?

[Mark_A]

I haven't yet had an adequate explanation of this, one person said simply that G wasn't sharing all search terms information anymore. Well that would be true to form as G have in the past removed data from webmasters which gave advantage, but then why would it still calculate CTR on this reduced data set effectively giving two very different CTR for what is the same triggering search keyword. I don't understand this.

[Mark_A]

Just went back from the Beta to try the old interface. I do prefer when my totals stay consistent.