Ok. You take off at a long runway. no obstacles. I speak for the B737. You derate, and probaly use ATM for your take off. Your engine rating is now 22k.
Your destination is 30 min further on, rwy with on the other end obstacles. In the event of a go-around here, you do not want to rely on a 22k derated engine, but full go around thrust. Especially if you would loose an engine. So TOGA (twice) can give you 26k..