Why the hotspot is not located in the position as I set?

Maybe you add hotspots when the images are in the "best fit" mode. The size of the images in "best fit" is not their actual size in the virtual tour. So the relative position and size of the hotspot will be changed when the images are displayed at their actual size.
In order to keep the hotspots the size and location as you set, you have to set and edit them in the "actual size" mode.