[rainabear]

I'd really like to understand this. I find no reference to character metrics on this site with the Composer manual.
http://www.ibmcomposer.org/SelComposer/Manual/toc.htm
What I do find, in the appendix, is a list of characters and their respective relative widths. - an A is 8 units thick, a l is 3 units thick, etc. This is how it does porportinal spacing. I assume that, combined with how the letter is centered in its block, and how far the machine advances with that letter composes character metrics. Right? There's no mention in here of variable character metrics depending on the next character, which is what you would have to have to do what we are seeing, right?
Also on this page, http://pfaedit.sourceforge.net/editexample5.html which talks about character metrics, it says under kerning:
If you are careful in setting the left and right side-bearings you can design your font so that the spacing looks nice in almost all cases. But there are always some cases which confound simple solutions.
Consider "To" or "Av" here the standard choices are inappropriate. The "o" will look better if it can slide more to the left and snuggle under the top bar of the "T". This is called kerning, and it is used to control inter-character spacing on a pair-by-pair basis.
In the example I posted, the a snuggles under the bar of the t, which is exactly what he is saying.
Either way, the width of the at and ta pairs in Word and the memo are the same and there is overlap between the tail of the a and the bar of the t. In the example of text someone posted on an IBM Selectric Composer, which is the typewriter all the apologists say could have typed the memo, there isn't overlap. This is because the a doesn't have much of a tail, which is why the Press Roman Font has similar spacing to the Times New Roman font, because it doesn't have all of the serifs to deal with that TNR has.

Whatever you call it, it's there in the memos and word, and it's not on the text from the Selectric using the Press Roman Font where someone tried to copy the memo, and got close, but not close enough.

[eclectic]

Yes, the differences are there, but they "can" be explained away by the poor quality of the copy (which can eliminate or extend serifs in either case, and even produce more severe distortions). I think all the experts agree now, that the most damning thing is the exact match of the whole text to MS Word. While each single feature of the memo can be explained away, let it be even in a rather implausible way, it is against all odds that all features "conspire" to match MS Word

Character metrics is computer terminology. It just refers to parameters describing a character, its width, bearings, etc. In particular different characters have different bearings from left and right. They are responsible for the effects you observe, there is no evidence of kerning (in precise, computer technology sense of the word) in the 'docs'.