It's because they're targeting certain demographics. Chinese believe 44 is bad luck, as it sounds like double death in their language. I lived in a CityPlace building where they skipped all the floors ending in '4' (4, 14, 24) plus 13 for extra measure (although I don't think the Chinese are averse to 13). At least it doesn't look like this building will skip all the floors ending in 4. Doing so would 'add' at least 5 floors (4, 14, 24, 34, 44). I'm guessing they're going to skip 4, 13 and 44.
I do think it's ridiculous to call it a 47 story building though. If that's the case, I could call my 2 story house a 100 story 'tower' (therefore making it the tallest building in Toronto) simply by labeling the 2nd floor as the 100th.