Consensus, and an acknowledgement that when two or three versions exist of a formula, they are noted.
Originally Posted by Photo Engineer
On that point Edward Lowe has D72 in his 1939 book with the rounded off weights, while you & I have the more accurate version in 1940's etc Kodak publications.
We have to take what a company publishes itself as Gospel. But there's a huge differance between a rounded off formula and an error, which of course can & does happen, typsetters made more before comuters