"Gone green" or "Offer completed"?

I'm not sure where to ask, but I figured this was the best place to ask. In the trade module, "Gone green" and "Offer completed" seem to be somewhat on the same levels... can someone give me a quick explanation how they differ? (Yes, I did read the rules beforehand.) )

Offer Completed means that they just completed the offer (but doesn't mean that the offer went through).. Gone green means that the offer has been completed and the offer has gone through..

not all offers are instant, so you mark it offer completed when you actually finish the offer, and you switch it to green once it has credited.

Yeah what they said.

Also, moved to Help! section.