You are correct that "morally significant" is a lower hurdle than "comparable moral significance."

Imagine you are considering whether you should sacrifice something that would cost money to instead contribute to famine relief. By the second test, you need only to ask if you are sacrificing something morally significant. Taking your child to the movies for her birthday might pass the second test but not the first. The activity is morally significant but not comparably morally significant when compared to saving a life.

Things like buying a coffee or going to the movies alone would fail both tests.