Burning 2 qt/400 miles has nothing to do with the type of oil you use.
You need to trace the oil that is coming from the exhaust area. I would think you would smell the hot oil on the exhaust if it was running all the way down the headers and to the tailpipe. You also need to determine if that is actually engine oil, or another problem in itself. If you have no leaks, then you are burning that oil. I'd do my CCV and hope that fixes it, otherwise you need new rings. You want this to be a leak, but like lcoleman said, there would be massive amounts of oil spilling out everywhere if this was just a leak.