Carowinds and anybody affiliated with them do not standardize or classify rollercoasters. They are enthusiasts just like you and me. I can guarantee you that there is nothing labeled 'Giga' in the B&M sales catalog. Their coasters taller than 200 feet are labeled Hypercoasters. There is no argument to be made. Its their coaster. Its their label. Which brings me back to the point that I made earlier, Marketing can 'technically' call 1305 the tallest giga and get away with it. Only Intamin labels their coasters with the term Giga. Just because everybody else in the coaster world 'adopted' the term, doesn't mean shit.
Edit....No coaster references here. http://www.thefreedictionary.com/giga-
Edit....No coaster references here. http://www.thefreedictionary.com/giga-