"is complete" or "is completed"?

[BWT72]

I notice that some of my peers used "is complete" instead of "is completed" in a sentence: "The project will move to the next phase after development task is complete." What are the rules for using "is complete" vs "is completed" in a sentence? Thank you.

BWT

 

[BWT72]

I saw a thread for this discussion dated 2005 by Casiopea. It stated that "complete" = all in order and "completed = finished". It is fair to assume that both are interchangeable?

 

[emsr2d2]

That explanation doesn't work for me. As far as I'm concerned, if something has been finished, it "has been finished" or "is complete". I would only use "is completed" when talking about the future.

The building has been finished. It was finished in April 2013.
The building is complete. It was finished in April 2013.
I won't pay your for the work until the building is completed.