You're referring to this thread:
Form vs. Increasing Weight
That's basically right, tfranc, except the end. This may just be semantics, but I wouldn't called them failed reps, because you completed the rep, showing you're strong enough to do them. But I would call them reps that are too deviant from the ideal model which you're trying to replicate every time, and which, over time, lead to a higher risk of injury and less than ideal recruitment of the right muscles that make you stronger. So you don't keep adding weight when your completed reps are of that poor quality.