Good afternoon, gents. We are currently updating our very old procedures for engineering documentation, and I am surprised at the amount of disagreement we are having. Long story short, we stick to using Numerical revisions for preliminary versions and Alpha revisions once released. Of course the released documents are always under CM control. The disagreement is in the area of the use of "preliminary" watermarking on drawings. For instance, a revision needs to be made, but other exercises need to happen before the full implementation of the ECN (quoting, review, etc). For this instance, let's say the drawing that will be revised is at Revision B. In this instance, the drawing is modified with desired changes and revision is updated to C, and clearly marked "PRELIMINARY". At that point, the preliminary drawing may be sent out for quoting, dfm analysis, or anything else. We have two groups of people that have the following two opinions:
1) If ANY changes are made to the Rev C drawing marked "PRELIMINARY", the drawing revision MUST increment (in this case, to D).
2) If changes are made to the Rev C drawing marked "PRELIMINARY", the drawing revision can stay at C. When the drawing is finalized and the ECN/ECO has been reviewed and released, it will be released at Rev C.
For option 2, if changes are made, either the file name would have a unique identifier to differentiate between the preliminary versions, or the original preliminary watermark will have a unique identifier in it, such as "Preliminary_01"

In your experiences, which method would you personally use?