RE:
First of all your math is not mathing. Those values do not add up to 9.49. They add up to 11 hours 49 minutes.
Secondly you aren't displaying everything. For example you are not displaying travel for a start. Also the times displayed when in h:m don't include seconds. Those will be added to the total though. When you add everything up properly you should find it much closer to the estimate.
RE: Slicer Time Calculations Wrong
Right you are, it's 11.49. Which is almost 2 hours less than 13.30. Seconds? That may add a minute. An accurate estimate isn't off by 1.41.
RE: Slicer Time Calculations Wrong
And have you turned on display of travel like I suggested ? You would be surprised just how much time is spent on travel as that also includes the lift on layer change and z movement is the slowest there is. Please show your legend with that on.
Also the point about seconds is that each of those entries that are in minutes and hours could have an 59s on them in theory. So while not much it could be several minutes extra when added together. But my guess without a copy of your project is the travel.