Pushing changed sources multiple times

Is there a way to push changed sources a second time?

I pushed the changed sources and it worked well. I then cleared the associated library, tried pushing the changed sources again and nothing happened. I understand RDi uses a timestamp to determine the changed sources, I'm just not sure how it does it internally.

Initially, I thought RDi checks the source member timestamp against those in the associated library and pushes those that differ. It's not the case as per my test so I'd like to know how RDi determines the "changed sources" in the hope that I can somehow tweak it to be able to push these changed sources multiple times if need be.

Thanks.
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