When a user executes any prolonged task, including downloading large files or copying many files, an interface such as the one below is typically displayed to keep the user informed of the progress.
These progress interfaces are quite ubiquitous, yet I can't help but see one inconsistency: Their time expressions.
In the screenshot above, Windows displays the estimated time left to "About 4 minutes", however I usually see just "4 Minutes" or "ETA 4 mins".
Does that mean there is less than 4 minutes left? (i.e. the estimate is rounded up) That would make the full time remaining be something like 3 minutes and 40 seconds. Or, is the estimate rounded down, meaning there is actually more than 4 minutes remaining?
What is the correct way of representing these shortened time expressions? Should what is displayed to the user be rounded up, or rounded down, and why?