Halls, I was thinking about what you said and I actually think it may be a benefit if you have your actual party split up. I don't know if this has changed, but in the past you were allowed to keep a cabin if the main member of the cabin was still cruising and then you can change the other people in the cabin. In the case of the OP if she has herself in one cabin and her DH in the other then IF the other family isn't able to go, she can still use that room for say another family to come with them.
Your thinking would be correct if they cancelled before any penalties set in. But I think HallsofVA was thinking more long range -- like what if something happens at the last minute thing and the family can't go? Then you are either stuck paying for the two cabins or paying penalties to move names around. I think that's why it was mentioned to weigh the benefits of having the CC in each room to whether you would travel with/without the other family. It may go smoothly, but if it goes bad right before sailing, you've made a messy situation messier.