NZC high performance boss Bryan Stronach said the decision on the ball was part of an overall position taken around a range of elements including pitch quality and what it wants for its leading cricketers.
"It's how we best develop our players and, at the very highest level, how we win games of cricket. That's the two things we look at," Stronach said.
"It's about how we prepare our pitches, how much the ball does from both a bowling and batting point of view and the skills we need to develop around that."
Stronach acknowledged it's a fine balancing act and arguments can be made for both the Kookaburra and Duke cause.
"We want the ball to do more because we need our batters to develop those skills," he said.
"[However,] that makes it easier for our bowlers ... and do we want medium pacers who can just come in and the ball swings round corners, or does lots off the pitch, which doesn't help develop our bowlers."
Stronach accepted seamers would pick the Duke to use every day of the week. He argued, however, that while batsmen would prefer to face the Kookaburra from a run-scoring point of view, from the perspective of skill development, some might opt for a Duke; and the same principle could apply in reverse to bowlers, who could see the benefits in mastering the Kookaburra.
New Zealand fast-medium bowler Matt Henry is going gangbusters in English county cricket for Kent. He's taken a whopping 37 wickets in four games at an average of just 9.5 runs. That is 13 more than the next most successful bowler in either division of the championship.
He's enjoying using the Duke but Stronach raised the question; has Henry's years of exposure to the Kookaburra contributed to his success? Theoretically, if he'd been brought up English, using the Duke, "would he be running in bowling as fast and doing what he can now? He might have found he didn't need to run in as hard and put the ball there [on a good length] and it would have done more."
It is a fair discussion point and cases can be made either way.
Stronach said there had been an element of loyalty towards a long-standing partner in the ball decision but that that alone would not have carried the day for the Australian manufacturer.
"They have been really good to us for a long time but that wasn't an overriding factor by any stretch.
"Kookaburra have been amazingly flexible. They've got a couple of types of balls but [are relaxed] if we wanted to use another ball. That's pretty progressive to me. It means we can be flexible enough to decide what we need, when we need it. We're pretty appreciative for what they've put in the game and for how long."
Stronach said Kookaburra had learnt much from the ball shape dramas of late and knows they are trying to prevent it happening but also there's an awareness you can get rogue balls in any batch.
