The last graph was exactly as it should be. Basically, please ignore anything where the paid-out value is no different from the predicted value, regardless of dropoff or profit.

The former represents a definitive bug, the latter likely just means the trade route demand is rather low (probably due to someone selling recently). It's the former case that's the biggest concern.. general re-tuning of routes and the overall economy is a subject for another time and another thread, and I'd rather not confuse the issue here.