Perhaps there's someone else who uses two decimal places who'll say something on this thread. At present I believe we log flight times in whole numbers of minutes, internally, so it would be difficult for us to change to something more granular than that.
Also, regarding the other issue, the next version of SkyDemon will make the rounding of flight log times consistent between our logbook feature and in-app log display, and should solve the issue where the maths looks wrong.