What does acreage “more or less” mean?

My understanding is that “more or less,” was originally conceived and used to reflect the inherent imprecision of early surveying instruments and techniques. A chain or metal tape, for instance, will sag a bit when stretched.

My sense of things, however, is that “more or less” has come to be used as a general shield for sellers who convey acreage short of what they’ve advertised and short of what the deed sets forth. Judges, I expect, will use some form of the reasonableness test to determine whether a short-acreage sale reasonably falls with more or less, or, alternatively, exceeds it.

I know of examples where relatively small acreages — under 50 acres — were short by ten acres or more, and the buyer was told he had no legal recourse because of “more or less” in the deed.

Would appreciate hearing incidents/examples from around the country.