For me it's the opposite, I find the seated version more strict and I when I started I had to use considerably less weight. I'm finally getting enough work in to see some results. I used to do them standing but found my back would curve, and the low point was when I tried to force up a last rep and felt a pop in my lower back. If you're doing them standing, remember to keep your back straight and don't push too hard for that last rep. Save it for the next set.