So, .capx is updated with the added conditions.
(Left out some information in my last post, sorry for that)
Now to "tilewidth * 1.5".
Refer to this very beautiful Paint drawing:
The condition used in the CAPX checks whether the user clicked any of the tiles 1 to 8 (numbered by you).
It does this by checking whether the user clicked ANYWHERE around the red tile. Since the red tile's origin (from where calculations start) is in its center, it's half the tile height/tile width away from the tile's edge.
So to get from red's center to the outer edge of the adjacent tiles, we need to add half of the tile's height/width plus another full tile height/width.
The condition now checks whether the user clicked anywhere between the outer edges of the 3x3 grid of tiles around the red tile.
Only when this is the case, a new red sprite is being created.