Hi AntySteve,
1) The first number is the application level timestamp in ms, and the second number is the raw timestamp.
2) Yes
3) Yes
4) The other option is to use "Start Logging", and create a log file set for a specific run. More information on how to use the logging feature is available in the "Getting Your Product Ready for ANT+ Certification" pdf. When you hit "Start Logging", it'll open a prompt where one of the options is to configure the log file location.
BK