At the start of his discussion of "Similarly Spelled but Identically Pronounced Variants":

The contribution of commentaries on the following text-critical discussion is minimal, since commentators as a rule follow the text of the GNT [UBS4] or NA [NA27] without further ado. Where they do take up a variation unit for discussion, they normally accept the verdict of the editors and the explanation supplied by Metzger's commentary, which they express in their own words. (Caragounis, Development of Greek and the New Testament (amazon.com), 518)

And he's right, but his comparison is wrong. In the setting of a commentary, unless it is focused on being a textual commentary, it would be questionable to devote pages and pages to each text-critical complication. It is right to mention them, but one need not work them out in painstaking detail unless that is the raison d'etre for the commentary. In the setting of an article on a variant, however (which is what Caragounis has done) one would be irresponsible to not work things out in significant detail, as Caragounis does in the next section of his book (the one dealing with variants at 1Co 13.3, pp. 547-564). And even in the current section (pp. 517-546) Caragounis usually only presents enough information to show that the variants are spelled the same, they sound the same, and the evidence is split.

But overall, he's right. When *most* commentators bring up a variant, they typically defer to Metzger and move on.