The rounding is not realised based on time entries. This would not make much sense: If you want to achieve the most information content with clockodo, you will add a new description for every subtask on which you work on. This is excellent for your evaluation, because you can exactly reproduce and categorize your working time. But rounding up each of this time entries, would falsify your billing completely. You meet with the same problem as soon as you have to edge another small task in while working for another customer.
That's why clockodo doesn't round your times per time entry, but based on the composition of your report. The first example image shows a report without rounding being activated. It refers to the project "Castle restaurant" and has the composition "Service" -> "Day" -> "Description". The second image shows the same report, but with rounding being activated to quarters of hours. While creating a report, clockodo groups all time entries together based on the composition of the report. On the last composition level of the example, all entries with the same service, the same day and the same description are grouped together. The respective durations and revenues are summed up and displayed for the group. When rounding is activated, the rounding takes place on exactly this last composition level / group level. You can recognize this by the symbol ≈ in front of the rounded values. On higher composition-levels, the already rounded values are just summed up.
You see, the rounding of values can be specified very individually. In this way it is possible to summarize tasks according to their description and round there durations and revenues up, but also to summarize just by services, for example.