I have in fact used a typewriter, though your post appears to evidence that you've never worked very much in the way of reading comprehension. It is indeed possible to reach an approximate center on a typewriter - even to the point that it is barely noticeable at the glance of an eye. It is NOT possible, however, to perfectly center three consecutive lines in block succession and have them match precisely with a computer-generated version of the same. To do so would be a freak coincidence with chances of happening somewhere in the one in a billion range.
The reason for this is simple and has been explained many times on this thread by myself and others. The mechanical method of centering a typewriter is substantially different from the algorithms used by a computer to center something. The mechanical method is based off of calculations made from the left side of the paper moving in a left to right direction whereas the more precise computer method is based around a central axis in the middle of the page with the text moving outward from it in two directions simultaneously. Hence the computerized centering will always line up precisely with the middle of the page and with all other computerized centerings of the same text in the same font and size (see the image). Mechanical centering will not because of imprecision that is inherent to even the most careful of centering methods.
Doubt me? Then let's try a little experiment, chief. Go pull out your typewriter and try to replicate the centered address block on the CBS memo. When you're done post it here. You can then compare it to the memo itself and the word processing version, both of which are in the image at the top of the page.
Try drawing a very slight, erasable pencil line down the center of the page. Then, using the the paper release lever, manually shift the paper to line up with the type guide.
Perfect? No. But as close to perfect as you can measure on a .pdf file posted on the Internet.
your post appears to evidence that you've never worked very much in the way of reading comprehension.
Please keep in mind, I'm on your side in this.