The summary is that currently, the client decides when to set the 0 point for the time stamp (essentially starting the timer). The current thought is that this should be done on the Arduino's side to keep the timestamp control as close to the data source as possible. There may be a performance trade-off for adding this overhead to the Arduino though.
Look at the conversation starting at 12-05-13 for details on this feature request.
https://opendesignengine.net/boards/4/topics/387
The summary is that currently, the client decides when to set the 0 point for the time stamp (essentially starting the timer). The current thought is that this should be done on the Arduino's side to keep the timestamp control as close to the data source as possible. There may be a performance trade-off for adding this overhead to the Arduino though.