I lack a military background, but worked as a machine operator in college. My dad was a master machinist in a development shop at a university that made things for NASA and various one-off projects. One year they got a young guy from Germany as an apprentice. My pop explained the tolerances on a particular job were very tight and when extreme tolerances were involved regular cutting oil was not going to, um, cut it. He had that German running around the shop for an hour asking every guy there where he could find some Maiden Oil. Everyone played along and the poor guy never caught on, probably due to English being a second language. I gather the grid squares (we're talking map coordinates right?) are along the same lines.