One fewer non-rule to follow

Though I don't frequent Starbucks, I very much enjoyed S.A.P.'s post about "Starbucks names," as did most of the many commenters. (A couple of cranks took the trouble to object that the topic was too trivial for The Economist's blog. Some people just aren't happy till they let you know they're unhappy.)

But I think S.A.P. (or "Sam," to Starbucks) commits an increasingly frequent hypercorrection when he says, "My Starbucks name just gives me a way to blend into bland normalcy: it's one fewer thing different about me."

Yes, one thing is definitely a countable. But "one less" is the preferred idiom, as Google's Ngram Viewer (insert cautionary language here) shows: 

Considering the reams of usage commentary (some simple-minded, some more accurate) on the less vs. fewer distinction, there's surprisingly little mention of the one less/one fewer issue. MWDEU, which goes on for nearly five columns about less and fewer, says simply, of less: "And of course it follows one," giving as examples "one less scholarship" and "one less reporter." 

Theodore Bernstein, in "The Careful Writer" (1965), suggests a possible rationale for this fewer avoidance:

There is one oddity about fewer: Whereas it is fine to write, "The Liberals won
three fewer seats than in the previous election," you run into idiom trouble if you reduce the number to one; you cannot say "one fewer seats," nor can you say "one fewer seat." The only escape hatch is "one seat fewer."

(He goes on to point out what less/fewer purists often ignore: that even countables may, in a given context, be considered as quantities rather than numbers. "For instance: 'Not many of these buildings are fewer than thirty years old.’ The thought here is not of individual years but of a period of time; therefore, less.")

And since the commentary is so scant, I'll mention that in Johnson's 1755 Dictionary, "one" is defined as "less than two" (not "fewer than two," though he's obviously referring to whole numbers).  

I don't think I ever heard the "one less" rule during my editing years, but if others did -- or if you have further citations on it -- I'd be interested to know the where and when. Google Books doesn't turn up anything, but it's not working well lately, so that non-result can't be trusted.

Update: I forgot I had some earlier research on this, from my column in the Globe in 2009 (when Google Books was more responsive):

Earlier generations of usage critics, however, certainly used "one less," even if they subscribed to the traditional less-fewer line. Here's John Russell Bartlett, from his "Dictionary of Americanisms" (1848): "To play dummy, is to play with one person less than the requisite number." Joseph Fitzgerald, in "Word and Phrase" (1901): "Total for these three languages 57, or one less [vowel sound] than for English alone." H.L. Mencken in the American Mercury (1925): "There is one hypocrite less in London today."

[Bryan] Garner notes that in nearly one-fourth of his current examples, "writers use one fewer, an awkward and unidiomatic phrase," where one less would be better. "One can't help thinking that this is a kind of hypercorrection induced by underanalysis of the less-fewer distinction," he says. That is: it's a mistake caused by simple-minded application of a rule that isn't really so simple.