Blocksize for lossless crop/rotation

When I select "Adjust crop area for lossless cropping" I expect that the crop area is adjusted to a multiple of the block size of the JPG. When I enlarge the area slightly and select "Adjust crop area for lossless cropping" again I find that the edges are now 16 pixels longer. So the block size of that image seems to be 16x16 pixels. However, the edge lengths of the adjusted crop area are not a multipe of 16. How come??
Second question on lossless handling:
What happens if I rotate a picture in cam2pc the edges of which are NOT multiples of the block size?
Achim
Second question on lossless handling:
What happens if I rotate a picture in cam2pc the edges of which are NOT multiples of the block size?
Achim