-
That’s entirely up to what it is you are trying to learn.
If you want to learn the cents per point of what you paid for the entire trip, then you would add the two points costs together the two cash prices together, and the two taxes and fees together, and then plug those total numbers into the equation.
If, however, you want to learn the cents per point of each flight, you do the equation twice, once with each flight’s numbers.
If you care to learn what you are paying compared to a round-trip price, then, yes, you would do 1/2 of a round-trip price (or, yes, discover the round-trip price, divide by 2, and plug into the equation).
Basically, what I’m saying is, to figure out the question you are asking first, and then set up the math to answer that question.