So if you can get to Toronto for a couple hundred bucks, it might be cheaper for you to fly via Toronto.
Not if I can get to Miami for $170, so no: not even from Chicago. (And BTW $614 US is what we actually paid, not what's advertised. You know, them applicable fees and taxes add up to $120 US, plus sharp things and bulky things that have to be checked in... you can wear your BCD on the plane but you still have to check in your trauma shears)