Google quietly announced on Google+ that they are combing/merging two different metrics into one metric on the mobile click front in order to appease the "feedback from hundreds of advertisers."
Starting the week of September 29th, 2014, “Mobile clicks-to-call” and “Mobile phone calls” click types will be combined in AdWords click-to-call reporting.
Google added, that this change will impact existing mobile click-to-call data, including historical performance data.
The data will now be combined and aggregated under a single click type: “Mobile clicks-to-call.”
As a result, you’ll no longer see a row for the click type “Mobile phone calls.”
Forum discussion at Google+.
