1950s 1957-1958 Frame Dimension errors in shop manual?

[wbdeford]

Is this a known error?  (It's page 4-9 from the 58 Supplement, but looks like a 57 diagram at the rear.)  If I add up 34, 62.88, and 29.12, I get 126" instead of 129.5" for the wheelbase. 

When I look at the 59 manual, these numbers add up to 130", which is correct.  I can't find a comparable diagram in the 57 manual at all, nor could I find any hoisting section in the index.

Seems to me the 62.88 has a typo in it, because it's a few inches longer on my SDV, if I am measuring it right.

Another likely error is in the two 12.5 inches.  I have 25 1/4 inches between two points that are a little further back, and closer together, than those spots.

[Cadillac Jack 82]

Could be there were so many changes in production with the 57-58 models.  My 57 was an early bird and some things didnt click in the manual.