I would say it's valuable to have Mounce's firsthand perspective on these things as a scholar of NT koine Greek, and one who has served on translation committees for the NIV & ESV. As he notes elsewhere in the book, "every translator knows" that translation is "not word for word, but thought for thought." It's all about communicating the meaning of a given passage, which requires interpretation as to the meaning of a given text so one knows how best to convey that in modern terms. It is never perfect. But like he says, too, it doesn't keep the gospel message from being conveyed.