Plans are basically life views for work items. EWM calculates based on the ownership and the iteration the plan represents all the estimated data for all work items in this scope. It uses the allocation ours, scheduled unavailability of the owners to the project/team area and the time left in the current iteration to calculate available hours. It shows projections based on the order of items when tasks will be executed, based on the current information. EWM also, in certain plans, shows how the percentage of estimates is. If you only estimate 3 of 3000 items, your plan is likely wrong. In plan views, you can use the work breakdown and roadmap views to get an idea when items are planned to be executed. This should help telling what the status of an iteration is.