Confirmed reports at a Google AdWords Help thread show that if you use the XML format for Google AdWords reports, you will be missing decimal values in the report.
The advertiser who reported this noticed the discrepancy when he generate duplicate reports, one in Excel format and one is XML format. The advertiser said:
When I generate reports in excel format, I get the right number for avg cpc with decimasl, and when I generate an xml format it gives me a different one without the decimal. e.g. In Excel it is avgcpc = 1.50 while in XML avgcpc= 1478393. I think there is a bug in the reports when converted to XML format.
AdWordsPro Stephen confirmed the issue and said he will follow up on why this is the case and let us know if it is a bug or a 'feature.'
Forum discussion at Google AdWords Help.