Unfortunately, the OP expects to be Platinum. If the average flight, statistically, has room for 90%+ (not 100%!) of the EXPs, what are the upgrade chances of someone who's behind all of them, and also behind all his fellow PLTs who got their tickets earlier? Not zero, obviously, as there's a good deal of variability around the averages, but not nearly as good as yours. That's why E+ is an important part of the picture.