Orchestration are effectively stored as DateTimeOffset format (see bellow screenshot) which is going even above the level of precision you described.
However they are not exposed as such to the directly end user on the list and this an interesting idea to do so
However, I also experienced, notably from the studio, mixed order of the execution logs as well.
Orchestrator is maybe not the place where this could be fix but maybe from the activity side on the studio.
Would you have an example of Orchestrator log details disordered showing a similar screenshot with the DateTimeOffset value?