License Statistics lets you import existing data from a number of supported log files, including FlexNet (encrypted) report logs. The imported data is 100% accurate and can be used for reliable billing.
License Statistics in real-time mode uses data sampling to gather statistics, which will have small inaccuracies. However, over time, you can easily see a trend, and for most real applications (where users use the application for hours), the results average out. So, while License Statistics' data sampling method is not strictly speaking 100% accurate, it provides real-time reporting and flexibility, and can be run on virtually any license manager.
Please see these other knowledgebase articles to better understand how License Statistics works: