All the files are stored not in terms of their actual size but in terms of their allocated size... Depending on the partition format (FAT16, FAT32, NTFS), the files are allocated a multiple of certain kb. Therefore, size of a file is different from the size allocated for it on the disk. For eg, NTFS uses multiples of 4kb (If I am not wrong). So, even if the actual file is only 100 bytes (many .ini files are very small), it will occuply 4 kb on the disk... If the file is 4.1kb actual size, it will occupy 8kb...
What is strange though is that the size on disk you have shown is less than actual size... Never seen that before...
Arun