He also knew that if the Lions finished second overall, they would be playing one of the Kiwi teams in the quarter-final. So while the Crusaders were getting smashed by the Hurricanes in Christchurch, Ackermann's frontline troops were resting up.
His top team have had two weeks to rest, train, sleep in their own beds and turn up at Ellis Park on Sunday in the best shape possible.
The Crusaders, on the other hand, had to recover after the Hurricanes, patch themselves up and hang around until today before catching a long-haul flight to South Africa.
The alternative was for the Lions to fly their best players to Argentina, hope they could take the points they needed and then scramble back to South Africa to face the Sharks, who have built form and confidence with two strong home wins.
Ackermann could see that the rewards of not taking his best players to Buenos Aires easily outweighed the risks.
What he will also have factored in is that if a New Zealand team did take the No1 ranking, they faced a high chance of playing another New Zealand team in the semifinals.
Given the competitiveness and closeness between the four New Zealand sides left, it is by no means inconceivable that if the Lions, if they can keep winning, could end up the highest-ranking side left when the competition gets down to two teams.
Even if they are not, Ackermann will be quite happy to fly to New Zealand for a final - knowing they beat the Chiefs in Hamilton this year and his top players haven't done any long-haul travel since early March.