Do you add an NPV to account for not getting the return until some date in the future? I.e., a 10000 pts/hr task might be better prioritized after a 100 pts/hr task if the duration of the first is two years and the duration of the second is two days.

(Yes, these are silly and inflated and completely hypothetical. I'm interested in how you solve them within your structure, as I'm a huge ROI fan.)