Why Custom Action Type 51 is Required

If you have always wondered why we need to anSet Property Custom action when there is already a Property table to handle it, then this is for you.
Suppose we have to create a property based on the value of another property - in that case we cannot use the Property table to handle this. There will be a circular reference in which one property would be based on the other.
In this scenario we use Set Property Custom Action. To affect a property used in a condition on a component or feature, the custom action must come before the CostFinalize action in the action sequence.