When you enter a value in the year column you are given several choices on how to distribute that value. What is the difference between Breakback proportionally and Breakback evenly?
Breakback proportionally will spread the value entered over the rollup components proportional to the values currently in those periods. Breakback evenly will spread the value entered in the time rollup evenly across the periods. Breakback proportionally will only be different than Breakback evenly when there are existing values in the time rollup. See below example.