No, it is definitely NOT a pity. What you are expecting is not how Microsoft Project works, nor should we expect it to work the way you want.

After planning your project, you need to save a Baseline for the project, which will capture the initial planned schedule of the project. As you begin entering progress in your project during the Execution stage of the project, you will be able to analyze variance between the current schedule and the original planned scheduled. In your case, the original planned Duration of the Manufacture task was 13 days, but the current Duration would only be 10 days. That would generate -3 days of Duration Variance, which is a very GOOD thing, as it shows that the task finished 3 days EARLIER than planned. Performing variance analysis in Microsoft Project is how you learn and grow as a project manager who uses this tool to manage your projects.