A big "thank you" to all who responded. The best answer: the earth is not flat.
I was sent the following link: search section, township.
I am very familiar with this link (EarthPoint) but haven't used it in awhile except to check out an example: when you go to the link, for example, and type in North Dakota, 5th Meridian (for all of the North Dakota Bakken), and then type in T148N-R49W, section 22, you will see that this "640" acre section is, in fact, 617 acres. Just one more reason why probating minerals is so expensive.
Elsewhere, they are asking why a 1280-acre unit has a well that actually has 1,284 acres. I think the "answer" the folks are positing is missing the mark. It seems pretty obvious to me but I will wait to see what others say.
The first response was that the NDIC had made an error. That is certainly incorrect. The NDIC is not in error here.