No need to avoid answering your question, since it had nothing to do with what I said.

But - the answer is "No', that is not what I meant. Just for the sake of clarity, in WWI, all AEF combat troops were rotated from the trench lines on a regular schedule, with one battalion on the front lines, one in reserve, and the third in support (at rest) in the rear. It was an effort to reduce combat fatique in the trenches (a problem the Frenchicon experienced early in the war). I think the rotation period was 10 days (front to support, support to reserve, and reserve to front), but it might have been a little more or less. In RVN, as in WWII and Korea, troops were "left" on the front lines for extended periods of time. Since RVN had flowing front lines, I probably should have referenced WWII or Korea, but my only personal experience was RVN.

Does that help?

Jim