The efficiency expert set the new minimum but it sounds like nothing changed to help you make the new minimum. It doesn't sound like the expert was much of an expert on efficiency.

I wonder if others are stressed out about the new expectations. Maybe there is someone you could discuss this with at work. It's helped me when I have been stressed to find a coworker that is feeling the same way and talk about it. It might not change things, but it helps to hear how others are coping. And, when expectations are tough to meet, I try to just focus on doing the best I can and try not to worry about what they think about the results. That is all you really can do.

I hope it gets better for you!