Mopar Muscle had a 'How To Set Up A 8.75 Rear' article some time in the mid or late '90s.
The part of the article that covered pinion depth, the measurement was taken from the carrier bearing parting line. That's fine as long as the parting line happens to be the center of the bearing bore, which it only occasionally is.

Errors are often found all forms of media, printed and broadcast. Maybe with the rush of deadlines creates the failures to catch errors.
Latest one I've heard/read was a recent episode of the US version of 'Top Gear', one of the hosts stated the Porsche 914 was the replacement for the 356.