A question about OIP3

OIP3=Pout+ΔIM3/2
in this formula, the Pout is the total power of the 2 test tones or the single tone's power?
In my opinion, It should be the total power. but it is said to be the either single tone's power in some paper.What is the exact answer about this?
Keep expecting the answer, Thanks a lot!

It should be the power that you are interested in the frequency

hi
pout is power of favorite single tone signal.
regards