"All you can do is recommend your client to a professional print shop and have the shop, which will know the specifications of its machines, take over from there." This is the very last line in the article, all of the information in the article is for desktop printers, not for high end RIPs which is what is at most print shops. LPI is still what matters for these... now digital presses are completely different than offset presses in this regard, the articles you shared would be correct in that instance.
Regards,
mnawij