We have heard of King Muchukunda and Revati/Kakudumi stories explaining time dilation.
We know 4.32 million years is equivalent to 1200 divine years. So 12 years (vanvaas period) is equivalent to 1.2 days in Swarg Lok. And we know that Arjun didn't spent the entire 12 years in Swarg Lok.
So my question is how long did he actually spend in heaven during which he even got cursed by Urvashi?