Jon:

The numbers provided by Petrie are his calculated values. I used his theodolite readings...see section 18 of his book.
Also.
Once the four corners were established, two diagonal lines were drawn from corner to corner for each pyramid with their intersects used as the center points.
Then the complete site is adjusted/rotated for the south base of G1 to align with the X-axis of the drawing. The builders could only reference from east to west then geometrically establish a north-south structure. Therefore G1’s south base was elected as the established east-west direction for the entire site and all of my drawings (see west alignment on the illustration). Petrie draws all measures with reference to our present north-south alignment and that produces a further difference in measure.

I will recalculate, but this has already been confirmed on several occasions.
Again,thanks for showing your concern.

Best.

Clive