Is there a difference in what is required of a woman observing 'iddah (waiting period) after a revocable or an irrevocable divorce?

A woman undergoing iddah (waiting period) due to an irrevocable divorce is required to observe ihdad (mourning) according to some scholars, such as the Hanafis and one opinion among the Hanbalis. However, it is not obligatory according to others, and this is the more preponderant view. As for a woman undergoing iddah due to a revocable divorce, she is not required to observe ihdad at all. Instead, she must remain in the house where she was divorced until her iddah concludes, and she must not spend the night outside of it.