When I say "I'll be there in a few hours, I mean about 2, 2 1/2 give or take.........I reserve several and more meaning many many more-4,6,8,10 hours! My friend claims "few" and "couple" cannot mean the same. I say they can.
"Couple" by definition means two of the same thing. On the other hand "few" should be reserved for those times where you are trying to express a number greater than 2.
Any time one is substituted for the other this just leads to confusion.