While happy with her side's first couple of outings as a starting point, Ferns' defender Joline Henry is clear: the performances they produced against England won't cut it against Australia.
She said there were far too many unforced errors in both tests, with frequent miscommunications on attack.
"While we had the best intentions and it might have been the right idea, the execution wasn't there and that cost the team a lot of possession, which we can't afford to do against Australia," said Henry.
"The reality is we need to land our passes, because that could cost us two goals on the scoreboard."
With Aitken and her assistant Noeline Taurua taking the opportunity to test a variety of new lines and introduce players to the test environment against an understrength England side, the Ferns were always going to struggle with their consistency over the series.
Eleven players were used in both tests and the constant stream of changes affected the Ferns' flow out on court, as the team took time to establish their through-court links.
Aitken will step down from the top job following the three-test series in Australia.
She said while the performances weren't as sharp as she had hoped, the priority for the series was blooding players and developing new combinations.
"It is about us growing our depth now as well and making sure that come next year the new coach will have new options available to her," she said.
"So we had to bite the bullet at this point in time, and probably it's only right that I can absorb that."
However with Australia set to provide a much sterner challenge than the English, Aitken acknowledges the time for experimenting is over.
"This first part was about getting everyone on court, but we will certainly be narrowing down our playing lines when we play Australia."
The Silver Ferns will stick with the same 12-strong squad for the Australian series, with medical staff advising that Pulse defender Katrina Grant had not recovered enough from a foot injury to rejoin the team.
It was hoped Grant would be fit in time for the series to bolster the experience in the defensive end that is already without captain Casey Williams.
But Aitken said it would be short-sighted to rush Grant back and risk doing further harm.
"We've taken the advice that this is the time for her to rehab properly," she said.
Silver Ferns v Australia
* October 23: Burswood Dome, Perth.
* October 26: Adelaide Entertainment Centre, Adelaide.
* October 30: Hisense Arena, Melbourne.