According to Dave, when the OMAC Packaging Workgroup was preparing the PACKML guideline for review and publication by ISA, the S88 Committee assigned the project as Technical Report ISA-TR88.00.05 Machine and Unit States: An Implementation Example of ISA-88. When the completed document was submitted for publishing, it was pointed out that calling this Part 5 might be seen as odd since Parts 2, 3 and 4 had not been published. I'm only guessing here, but perhaps these numbers had been assigned to other projects that had yet to be completed. The PackML work always seemed to me to proceed much more quickly than other standards efforts of this type.
ISA determined to publish the final document as ISA-TR88.00.02 Machine and Unit States: An Implementation Example of ISA-88. This meant that the previously finalized draft needed to be have all of its references updated. But a lot of contributors and reviewers of the draft had copies of the document in its Part 5 configuration. These copies, as well as copies containing references to both Part 2 and Part 5, have made their rounds through the industry. Many, including me, were not aware of this change, and continued to refer to the PackML document by the wrong number.
So, if you don't yet have your copy of PackML, or if you have a draft copy, it is best that you go to ISA's site, put down your $95 fee, and get the official latest version. We must also break the habit of referring to it as Part 5 or TR8.00.05 and begin referring to it as Part 2, TR88.00.02. We should also probably be referring to it by it's official name, but somehow PackML just rolls off the lips much more easily.
For those of you who have been applying PackML, no matter what you have called it, my readers and I would like to hear about your experience. If you've reviewed the documents and decided not to apply it, we'd like to hear why. And if you are a machine builder and haven't even reviewed it, why not??? Just take a minute, scroll to the bottom of the page and leave your comments. Stop back in a week or two, and review the thoughts of your peers. There needs to be much more dialog taking place on the topic of PackML!