3. High Performance Sport New Zealand reduced SNZ's annual funding from $1.3 million to $900,000 in December 2016, despite the sport meeting 24 of 26 key performance indicators in its strategic plan.
4. Coaching staff Gary Hurring and Donna Bouzaid had their roles disestablished in March.
5. Corey Main, in the 100m backstroke, was the only finalist at July's world championships in Budapest. New Zealand's 10 athletes - in the pool rather than open water - swam 29 races and produced four personal bests.
SNZ chairman Bruce Cotterill described Olszewski's exit as "a disappointment, but not a setback".
"It's one of those genuine family cases. Jerry's got elderly parents who have taken a turn for the worse, and he was down in New Zealand feeling guilty - like we all would - in those circumstances.
"It's regrettable because we like him, but it does highlight the risk of employing people from overseas sometimes when things occur that prompt them to reconsider [their position].
"If it happened the year before the Olympics it'd be a setback, but at the moment we've just had a world championships with mixed results. It would've been good if he'd stayed, but the timing is not absolutely critical."
Cotterill said it was time to think carefully about a successor.
"There was quite a lot of interest at the time [of Olszewski's appointment] so we need to see whether some of those people are still keen.
"We didn't get a lot of New Zealand coaches putting their hands up, which is something I suspect might've changed."
The Swimvortex website claimed Olszewski was at odds with SNZ "over the federation's Olympic strategy and how that and other issues did not match the job description".
Olszewski told Radio Sport such allegations were "just not true" and that family came first.
"My dad is getting older and he has to have surgery. I'm the only one with the financial situation to take care of him.
"Obviously there's been a lot of change [at SNZ], but it was change rather than turbulence. The high performance team has stuck together. We were working as a team to make the best of some drastic cuts to funding.
"Steve Johns is the third CEO [chief executive] I've gone through. We also lost high performance director Katie Sadleir, and two key people beneath me in Donna Bouzaid and Gary Hurring."
Olszewski was asked whether he agreed SNZ's measures of achievement needed a dose of realism.
"I think there are some unrealistic expectations. There is a higher participation in swimming than any sport in the world. New Zealand's population is small and some of it is a numbers game.
"We've been fortunate to have some true global champions in Lauren Boyle and Danyon Loader. People need to recognise their achievements on a global level.
"I'm leaving on a high note, I don't have any animosity with Swimming New Zealand."
At the time of his appointment, Olszewski was described as "excited" to take on the role and move to New Zealand for a job which received more than 30 applications.
"I will be setting expectations and not settling for anything less than their best," he said.
"Obviously I am looking forward to working with some great staff and also with swim clubs and coaches around New Zealand to help create an environment where we can develop successful swimmers and good young people for years and Olympiads to come."
