You are correct about the Lettieri website. I think it is just erroneous information since I know for a fact that the LaValle San Marzano tomatoes shown at the site are grown either in the Agro Sarnese-Nocerino region near Naples (with the D.O.P. designation) or around Agro Sarnese-Nocerino. (The can in the photo is the non-D.O.P. version). Also, the AnnalisA and Geraldo diNola San Marzanos (to the extent they have the D.O.P. certification) are grown in the region of Agro Sarnese-Nocerino. I have been building a list of the sources of the "true" San Marzano varietal and it now includes the following names: La Valle (which also has the non-D.O.P version as mentioned above)., Strianese, Famoso, La Regina, Italbrand, La Fede, AnnalisA, Cento, Vantia, Gerardo diNola, viviTALIA, and Pastene.
I found your description of the Monte Pollino tomatoes amusing. I have learned not to put much stock in what is said on a can of tomatoes, especially if the price doesn't match the hype. Not too long ago, I bought a few cans of "Tuscan" tomatoes, at $0.77 a can. The label said "bionaturae Organic Whole Peeled Tomatoes", with the tag line "Rediscover the Precious Tuscan Tomato." Elsewhere on the label it said "bionaturae organic tomatoes are grown in sienna colored soil, ripened on the vine in warm Mediterranean sunshine and hand-picked and packed the old-fashioned way. Taste these tomatoes and rediscover a flavor delicately preserved in time and unparalleled today." After tasting them, I would put them just below the "fake", domestically-grown San Marzano tomatoes you mentioned the other day. And recently, I saw them in an upscale food market for close to $3.00 a can. I felt like putting a sign "Don't buy these" on the shelf.
I'm always looking for a good price for good (D.O.P.) San Marzano tomatoes, but I have yet to find them at bargain basement prices.
BTW, if you buy the 6-in-1s from the Escalon website (at escalon.net), the price per can for a 6-can purchase is $2.50. Shipping charges for the 6 cans is $1.50, for a total of $16.50.