"It's a difficult situation, when you're so many runs behind," Steyn said.
"How do you go about your batting? Do you attack, do you defend. It is difficult to decide which way to go.
"They haven't found out if they want to attack or defend certain balls. Then they do play an attacking shot and get out, then go back to defending and get out.
"It's a tough one. I can see where they're coming from and it is quite difficult."
Steyn, who topped the averages with 13 wickets at just 11.53 each, benefited five times from the edges of New Zealand bats; so, too, world No 2 Philander, and he played just the first test.
Morkel grabbed four wickets in that fashion, Jacques Kallis three, Kleinveldt two and Peterson one.
Edgy batsmen
Twenty of New Zealand's 40 dismissals in the two tests fell to catches in the wicketkeeper-slip cordon.
3: Dean Brownlie, BJ Watling and Doug Bracewell.
2: Martin Guptill, Daniel Flynn, Kane Williamson.
1: James Franklin, Brendon McCullum, Colin Munro, Trent Boult, Neil Wagner.