The object code is significantly less then the size of the binaries, Mach-O files (and ELF files and PE-COFF files) zero pad sections, allign them and generally have extraneous sections.

The boxes are the same, the content is different.

    > cat touch.x86_64 | perl -p -e 's/\0//' | wc -c
    19407
    > cat touch.i386 | perl -p -e 's/\0//' | wc -c
    19408

    > otool -tV touch.x86_64 | wc -l
    742
    > otool -tV touch.i386 | wc -l
    808

Hmmm.

So, now what? The article mentioned Lion's touch(1) size, and I wanted to point out that it actually covers two arches. We know there is padding, alignment, headers and density whatnot. The end result is that makes a negligible difference between the two arches, hence "~half".