Income risk- is it stable?

CFA Level III
#1

Income risk is important for comparable assured income streams, which can be more stable and dependable in a portfolio with long maturities.

Apparently from a mock exam this statement is true.

Can someone explain why?

#2

I have no idea what they think they mean by that.

First of all, “assured” should be “ensured”; but that’s the least of the author’s worries.

I’d imagine that they’re trying to say that if you have an ensured income stream for a long period, your portfolio is more stable than if you have an ensured income stream for a short period. It would be nice if they would say as much.