Why is the date of the last update different from the date set in the update schedule?

Example: 

You set your Inkspace update to 10:00 a.m., but the update history shows that it was made at 10:30 a.m. This means that the update began at 10:00 a.m and the process was completed at 10:30 when all data was updated (import, Inkspace, export). 

In the update history you can see the time of completion, because it is more relevant in relation to the data shared with your publisher. The duration of the update depends on the number of products in your Inkspace.