We recently announced a 
new flexible conversion counting option feature in AdWords that may affect AdWords API v201309 users. There are a couple of additional changes in the AdWords API v201402 that we want to bring to your attention so you can take full advantage of this offering:
  - Record conversion values in conversion report columns based on the flexible conversion counting option
- Retrieve and set flexible conversion counting options in the ConversionTracker
- Adopt new conversion-related column names in the reports
Flexible conversion counting option
Since February 25th, 2014, AdWords users have been able to 
change the conversion counting option between 
All Conversions and 
Unique Conversions. The conversion counting option is defaulted to 
All Conversions - when left as the default option, your conversion related values in the reports will not change.
If the conversion counting option is changed from 
All Conversions to 
Unique Conversions, then the following conversion-related report columns will reflect the counting option selected across all reports:
  - ConversionsManyPerClick
- ConversionRateManyPerClick
- CostPerConversionManyPerClick
- ValuePerConvManyPerClick
- ValuePerConversionManyPerClick
- ConversionManyPerClickSignificance
- ConversionRateManyPerClickSignificance
- CostPerConversionManyPerClickSignificance
Please see 
the help center article for specific examples of how counting 
Unique Conversions differs from counting 
All Conversions.
Retrieve and set flexible conversion counting options
In the AdWords API v201402, you will be able to retrieve and set the flexible conversion counting option. Please review the 
ConversionTracker API documentation to see the new flexible conversion counting options field named 
countingType.
New conversion-related column names
Conversion-related columns will have new names in reports. In AdWords API v201402:
  - The selector field names will remain the same
- The display names and XML attribute names will be renamed
If you are downloading XML reports, you will need to update your client application to read the new column names.
Please see the 
migration guide for a mapping between old and new display names and XML attribute names.
If you have any questions about this upcoming change or anything else related to the AdWords API, please contact us on the 
AdWords API forum or via the 
Google Ads Developers Google+ page.
 - Ray Tsang, AdWords API Team
 - Ray Tsang, AdWords API Team