question

Just to be sure that there are no misunderstandings about what that option does:
The field value is updated every time it is accessed, such as when viewing the list entries as a table, as long as the "Dynamic" checkbox is checked.

The "Reevaulate All Values On Push" option means that anything that is currently waiting to pull something from the list ("Backorders") will check if it can pull any value on the list, instead of just the new one.

This is useful if the pulling object filters for certain field values that change over time, like the "Unhappy Customers" sink. When the sink first tries to pull something or when a new customer is pushed to the list it will not be pulled because the wait time has not reached the threshold yet. The waiting time value can pass that threshold (as mentioned above, it will update whenever accessed). However this will not automatically make it get pulled, since it was already checked previously and deemed to not fit the condition.

So you have to tell the list to also re-check older values again by checking that option.

Below those options you can add other "Reevaluate Events". For example an item/customer leaving the queue or a fixed timer.

You can also use the following command in any trigger of a Custom Code in Process Flow to reevaluate all backorders of a global list.

List("ItemList1").reevaluateBackOrders();