Apostrophe overload

I am currently revising some user-facing documentation for a new client. The existing documents were prepared by a member of staff, no longer working for the company concerned, who had never had any training in technical writing skills. There’s a series of about a dozen Word documents of about 20 pages each. All the formatting has been done without the use of styles, additional white space has been added with empty paragraphs, and all the graphics are floating. Even the Table of Contents has been created manually. These are all examples of inefficient ways to use Microsoft Word, and they are typical of work produced by people who are, in terms of their documentation skills, well-meaning amateurs. (They may well excel in their own professional fields, and they are probably really nice people too!)
I can deal with all these things, and if I am asked to, I can show people how to save time and energy by doing things in different ways that allow for consistency and repeatability across document sets.
The thing that has really upset me with these particular documents is the poor quality of the writing itself. The most grating offence against accepted current usage that this writer is guilty of is the use of an apostrophe to indicate the plural of nouns. I’ve seen “operator’s”, “user’s”, “extra’s”, and “area’s” – not one of them indicating a possessive – in just a few pages. Poor Lynne Truss would be having a fit by now, and to tell you the truth, I am nearly there myself.