I was caught up in the excitement of using the symbol font. 
Let’s see if I understand your proposition. We can have two situations:
A) Add hot coffee to cool cream. Theoretically this will temper the temperature of the coffee and thus the heat transfer rate will be lower.
B) Add cream to the hot coffee. Doing this allows the hotter coffee to sit in the cup for longer, thus giving off heat at a higher rate while you smell the cream to make sure it’s still good.
My only problem is that even if the coffee is giving off heat at a higher rate, eventually the temperature of the coffee with cream added will equal that of the cream with coffee added. From that point out the two heat loss rates should be the same.
Am I missing something?