I see in the help file that Plan Estimates are "Record how much effort is estimated to complete the user story. This field is a real number and can accept three digits followed by a decimal and two more digits. The units are defined by your administrator. This field is rolled up (accumulated) from child user stories and displayed as a total. Estimates are rolled up and reflected on the Iteration Status page."
Has this been a recent change? Did Epic stories always have a roll up in their plan est field for their child stories? Or was this a recent update?