You can make changes for the previous day(-s) in History.It is useful for people who work with tasks after midnight, or just for everyone who wants to assign/reassign tasks retrospectively.
What we're working on:
Brush. It will allow you to choose a custom time range on the chart, and simplify assign and reassign operations for tasks.
Productivity Reports for activities. You'll be able to compose the summarized report for your website and app usage for the week/month/etc. Productivity score included!