You have raised a very interesting point, before taking this class I did not know all these terms, I used to only say that we were under budget, ahead/behind schedule, etc. In my particular case, during my capstone project, my team proposed an original budget of $150, the real price of our product was $90 but the professor, advisor and the team agreed to order some extra parts just in case we broke some fragile devices. By the end of the term, our cost variance was positive, however the schedule variance was negative (behind schedule). This occurred because during the project, we replaced a part for one that could do the job in an easier way and cheaper, but it took about 2 weeks to get this one part which made us have a negative value for our schedule variance. At the time I was not aware of these terms but now I realize what the correct way of expressing it is.

Let me know what you think.

Sincerely,
Roberto Pineda.