The open end activity is the activity that does not have any successor. Normally open end activity is not accepted in schedule because the total float will be calculate from the end of the project and these entire activities late dates gather at the end of the project and cannot be prepare a logical late start plan.
What is the difference between Retained Logic & Override Logic in progress update?
If a project is generally running according to plan and activities are not progressed out of sequence then there will be virtually no difference between the two methods. BIG differences come when activities are progressed out of sequence.
I believe in retained logic. Invariably that will produce the longest critical path but if activities have been progressed out of sequence, there could be some resulting illogical dependencies remaining, in particular resulting from dependencies with durations.
Progress override invariably produces a shorter critical path and again there could be some illogical lack of dependencies resulting from activities having been progressed out of sequence.