It's a personal preference really, but making the global change can cause unintended consequences to your tasks. I'd test it in Preview first. By changing to Calculated Work, I believe you'll lock your Planned Hours field. So you would only be able to change Planned Hours by changing the Duration or Assignment %. This is the reason we don't use Calculated Work. We don't like locking the Planned Hours. We use Calculated Assignment. Only because we prefer to enter a Duration and Planned Hours and let WF calc the Assignment % for each assignee in the task. We use the Planned Hours to estimate our labor costs for the projects. So it's very important to us that we can easily adjust them. Calculated Work will ask you your Duration and the Assignment percentage (Resource %) for each assignee and then Calc the Planned Hours (and lock them). Again its just a preference on how you want to operate. And a PM can always change their Tasks to their own preference as their creating them.
