I'm not familiar with these types of calls, but might it be possible he's trying to avoid getting into the nasty bits in front of all of the investors collectively in the hopes of swinging back around and dealing with them individually?

I've found that strategy to be pretty effectively employed by "perception management" types elsewhere. You know, guys with "reality distortion fields?" When you have a large group of people you're trying to maintain context for, you can end up getting into circumstances where you can get caught at giving contradictory statements more easily. Once the group catches that, they tend to dig and twist, and have further ammo for doing what you, the presenter, DON'T want.

Isolating said group members allows you the luxury of being able to devote your full attention to spinning the perception you're managing to only show what you want them to see without getting caught with your pants down by someone else you spun a yarn for previously.

I could be wrong of course, but I've seen it before.