we once had a technical editor on staff. Then budget cuts eliminated that, so we used a contract editor on a project by project basis. Then budget cuts eliminated that. So they said "Red, you read a lot, you can edit final reports now". Like I need that crap on top of my real job. People don't understand the difference between an editor and a proofreader.
I have an uncle who worked for the States Item for 40 years. He did double duty as a writer and a proof reader. He told me when I was young that he always caught other's mistakes when proofing their articles but always had someone else proof his own. Said you tend to read what you wanted to write instead of what you actually did write.
I see mistakes sometimes when I'm reading but to have to read anything just to proofread it must be a boring job. How could you enjoy even the greatest novel ever if you had to keep focused on looking for typos?