Here are the "errors" that you so correctly point out. I am quite aware of these.
East - West error is 559.07 - 558 = 1.07 cubit
North - South error is 631.05 - 629.9 = 1.15 cubit
Why it appears that it is out COULD BE because of the fact that The Giza Plateau and the grid used is not exactly 90 degrees to the distances and the actual lines and bases of the pyramids involved. I am working very hard to try to come to terms on why this error appears as there is no doubt in my mind that a 9/11 grid is used and 39.37 fits too perfectly to be a co-incidence. The error appears to be about 1 cubit.
Cheers and thanks for your comments !
PS: 1 MU is the distance of the closest approach of Mercury to The Sun and equals 46,001,200 km