I also see this issue. In addition the data is not in order, with the timestamps of some datapoint more that 1/2 second after the previous one then more data that was fractions of a second after.
I want to Sync data in time for two or muses and this seems nearly impossible due to not knowing what the real time of each sample is. While most of the data seems to be within 1/10th of a second (which is already loose) these 1/2 second jumps are worrying me. I'm logging the data on an iPhone 6 plus.
I would like to up vote the need for accurate timestamps.
It would be great if either
1) MuseLib would interpolate the actual (best guess) timestamp and also provide the uncertainty.
2) The museStat examples would include code to calculate an accurate timestamp and uncertainty.
This is needed to be of use for any type of scientific experiment that involves events happening in real time or comparing data from more than one muse.
In designing the 2018 model please have museIO send the time to the muse and then stream the actual timestamp or milliseconds after back so an accurate time can be calculated.