Hey @Il-Taek Kwon
I understand that you need more precision in your timestamp value, long format is one way to do it and it gives a precision of 15 digits after the decimal.
You can also use datetime function instead which converts your timestamp to datetime object, which have higher precision than their numeric counterpart.
time = datetime(timetable_data.Timestamp, 'ConvertFrom', 'datenum');
Note that, unlike the "format long" method, which only affects the display of the data, creating datetime objects maintains the actual precision of data.
You can refer the following documentation for more details:
