Yes, it is possible to output tenths of minutes in customer´s timetables. However, this option is only rarely used since this kind of output is usually used as customer information and in this case only whole minutes are typically output. For this reason, the corresponding menu option is somewhat hidden in the settings

If you still want to output tenths of minutes in customer´s timetables, for example for an internal document, you will find the corresponding menu option in the customer´s timetable under:

"Edit" -->"View" --> "Layout and content" tab page --> "Rounding rule for arrival and departure times" --> three-point button [...] --> "Show tenths of minutes".