This is in preparation for a larger change over the next couple of months to reflect changes AdWords is making to conversion reporting (some of which started about a year ago). In a nutshell:
AdWords will stop tracking 1-per-click and many-per-click conversions
AdWords now reports conversions in two columns:
All conversions - Reports the number of conversions from all conversion actions
Conversions - Reports conversions only from those conversion actions that have been configured to surface in this column. For example, an advertiser can exclude a conversion action that tracks additions to a shopping cart and instead only include conversion actions that track shopping cart completions.
As a result, columns in the DS reporting API will be changed as follows:
adWordsConversions: As described above, the data type is changing to a fractional Number. The data in this column will depend on the report's date range.
If a report's date range:
Starts after AdWords stopped reporting 1-per-click conversions, the column reports on conversion actions that have been configured to surface in the AdWords "Conversions" column
Ends before AdWords stopped reporting 1-per-click conversions, the column reports on 1-per-click conversions.
Overlaps with the date AdWords stopped reporting 1-per-click conversions and started reporting specific conversions, the column includes both 1-per-click conversions and conversions from the AdWords "Conversions" column.