Tier-2 nations complained about ultra-condensed schedules - Russia played four games in 16 days - while top nations played on weekends for better ratings. The IRB changed the rules in 2013, declaring every team would have a midweek game in 2015.
"That awkward start, with a Wednesday game and a Sunday game, we are training as two teams," Larkham said.
If Australia, Wales and England all record one win and one loss against each other, the for-and-against tallies against Uruguay and Fiji could determine who makes the quarter-finals.
World Cup-winning captain Nick Farr-Jones has questioned Cheika's selection policy.
"I'm not sure whether that's good or whether that's bad - that we don't have a settled XV," Farr-Jones told foxsports.com.au.
"When I think back to '91 and the success my team had, we had a very settled team, we had very settled combinations.
"I always think that it's much better to have your starting XV well organised, well prepared, with combinations that have worked in a year or two preceding."
- Daily Telegraph