As per documentation, traffic should be commited to log files at regular intervals in format: IP,timestamp,...
Each line should represent byte counter values during last interval.
After inspecting cdf logs I have noticed that on occasion same data is commited twice.
For example, time interval for commiting to log.4.0.cdf should be 12hrs, or 43200s. However, some log entries are added before the interval expires, and then again when interval expires.
In line 1 data is commited, then in line 2 after 43186 seconds new data is commited, but since 12hr interval has not expired yet, counters were not reset, and after further 15 secs same data is commited again in line 3.
Approximately 60% of log entries have this anomaly, which leads to significant error when reporting data.
For example, data counter on my ISPs side (whose accuracy I am unsure of as well) tells me that I have transferred cca 180 GiB during last 72 days. For the same period, bandwidthD reports traffic volume of 301 GiB.
Perhaps I misunderstood log file logic, but if I haven't this could be a significant error.