FWIW I contacted Digitalrev and had a lengthy discussion regarding the No.3 AC Close Up filter I ordered. I asked them to tell me specifically if the item detailed in my order confirmation was, in fact, the Kenko AC No.3 2 element achromat close up lens. In the end I did not get a satisfactory answer. After I receive the item I will follow up with another post. I guess it's possible that the support person I discussed this with was not familiar with the differences in these lenses.
Today I received an email from Digitalrev.com stating that the Kenko AC close up lens was not in stock and that they did not know when it would be in stock. I have requested a refund.