Read the man pages when in doubt.
man ls
shows the following:
-l use a long listing format
-s, --size
print the allocated size of each file, in blocks
-h, --human-readable
with -l and/or -s, print human readable sizes (e.g., 1K 234M 2G)
Without the -l you do not see all the permissions, owner, size and date information of the file.
The -s means to print the allocated size of the file. The 193K you are seeing is the actual size. The 204K is the allocated size as the drive is divided up into 4K clusters. 204K / 4 = 51 as that means the file takes 51 clusters.