There are levels to good technique. And what you have to do to make it better changes as you develop.
When you say the phrase “technique work” to most powerlifters, it conjures images of light training with a focus on body positioning. Perhaps even with an exaggerated slow tempo. And that’s fine for a basic competency in technical execution, but that’s about all.
As you advance, technique advances on two fronts — the details and the difficulty.
Once you’re into your intermediate stage, if you’ve been paying attention, it’s likely that “technique checks” with your back-off sets and low RPE sets yields no meaningful criticism. That’s fairly normal and intelligent. Your technique has likely settled to a point where you don’t have obvious flaws and what flaws remain are difficult or impossible for outsiders to observe. That doesn’t mean they aren’t important — just that they’re not observable. Oxygen is important, but you can’t see it either. There are also individual idiosyncrasies with your technique that savvy coaches are well-advised to leave alone. These are all technique details that must be attended to as a lifter advances.
That’s not to say more notable flaws are non-existent. But it will take more and more load for them to show up. The technical flaws have progressed in difficulty. Your lighter “technique sets” may look perfect, but the 2nd and 3rd attempts might have breakdowns that keep you from further progress. This sort of technical error is often different in character. It’s usually not a lapse of attention such as incorrect foot placement or hand spacing. It’s usually a dynamic error — didn’t brace hard enough in the squat, touched too low in the bench, or didn’t tighten the lats enough in the deadlift. Interestingly, some of these errors aren’t really errors with lighter weights. For example, bracing is only insufficient if it’s not enough to stabilize the load and provide force transfer. The heavier the weight, the harder the brace. So your light “technique” sets don’t really challenge this. You need exposure to heavier weights to practice this skill.
The solution in both cases is to provide a sufficient challenge to the athlete. If your bench bar path only ever breaks down with 85%+ loads, then training 50% tempo work isn’t challenging the qualities that you need to work on. You’ll have to start pushing that boundary in ways that allows the athlete to succeed if he works hard at it. That provides the stimulus for technical development and continuous improvement.
PS: In the RTS Training Lab, we have coaches who review videos for our members providing feedback on technique, weakness analysis, and programming modifications.