Well... in theory they should be. I published a book a while back through a publisher, and they assigned me a copy editor and a technical editor. The copy editor was amazing - it was clear she didn't understand any of the technical details, but she spotted flow errors and minor grammatical mistakes in dense technical prose. The technical editor, on the other hand, seemed to have (maybe) skimmed over the content and his only feedback was that he didn't like my writing style very much and left it up to me to verify all of the technical content. I did take it seriously, though, and I am proud to say that very few technical errors have been reported.
Well... in theory they should be. I published a book a while back through a publisher, and they assigned me a copy editor and a technical editor. The copy editor was amazing - it was clear she didn't understand any of the technical details, but she spotted flow errors and minor grammatical mistakes in dense technical prose. The technical editor, on the other hand, seemed to have (maybe) skimmed over the content and his only feedback was that he didn't like my writing style very much and left it up to me to verify all of the technical content. I did take it seriously, though, and I am proud to say that very few technical errors have been reported.