It doesn’t hurt to try. You lose nothing by asking.
As for whether the USC experience would be worth the extra cost, I’d say it depends on your family wealth, which we won’t pry in to. But my rule of thumb is that if your parents have to stretch financially to pay, it’s likely not worth it but if it’s a matter of receiving it now or as an inheritance later, then it is up to you (the difference can be a pretty sum when compounded over decades—let it compound for 4 decades and it could fund a large portion to all of your retirement just by itself, depending on how the market does). As for grade deflation at the top Canadian unis, sure. But American programs are aware of the rigor of the top Canadian unis as well. A top GPA from McGill/Toronto/Waterloo really means something. Also, for something like the MBA (several years after graduation), GPA won’t be one of the most important factors.
However, European programs (definitely UK ones) seem to have much more rigid cut-offs.