floydmcw
Prince
I saw such situations in the late game when you deal with 1Resource => 12cpt. Early on It is common to jump into 1Health => 2cpt straight after Currency and a bit later you can improve deal to 1Health => 5-6cpt.
In my experience the recalculation to a lower GPT happens when renegotiating luxuries, but not health resources. I assume this is because the loss of the luxury has a negative effect on the AI's economy.