[cypher]

Hi & welcome to HC.

It does seem that pairs do better in a smaller cage, a larger cage can give them more space to become territorial over & that can cause them to fall out.
What cage size are they used to? If they've been in a smaller cage until now than the larger cage could be a bit stressful for them along with the move to a new home.
If you don't have any levels in the cage, no shelves or ledges, & have plenty of little hideout places (always with more than one exit) they may be ok. It's very hard to be sure with pairs though, many do fall out as they mature so be prepared just in case.