Thank you for Contacting me.
The GPS update is an easy fix. By default it is set to record every 2 min or 50 ft. Change these both to 0.
o GPS Refresh Time (default = 120 sec)
The time between GPS update of location, regardless of movement. Enter time in whole number seconds.
o GPS Refresh Distance Unit of Measure
The unit of measure for GPS Refresh Distance, feet or meters
o GPs Refresh Distance (default = 50ft)
The distance traveled before the GPS updates the location, will override GPS Refresh Time.
The Log is set to record in whole seconds as you are seeing, I didn't think anyone would record less than whole seconds as the data log gets huge, at your 0.25, that is 14400 logs per an hour and most folks go out all day.
At a quick glance, I should to be able to simply add milliseconds to the time stamp and add this to the next release. If the data tables need to be rebuilt, then this would delay it a release.
If you have any other questions/comments, please let me know.