Value or Return on Points

I'm trying to calculate what return Le Club Accor gives me when earning points. For better or worse, there are no free nights or award tiers, just 2000 points=40 euros in value, which can be used to book or at checkout.

On a recent stay, I received X points for an outlay of y dollars. My formula was to convert the points to dollars, via euros and divide by the total outlay, giving me the percentage of payback. Since they are always worth the same, shouldn't that be about right?

BTW, I am about to set aside some time and peruse the threads to see if there is anything I know about to give rather than take advice.