Is there any reason NOT to upgrade?

I've been doing all my spending on this card to try and request a larger credit line in 2-3 months. If I upgrade to the QuickSilver, will it "reset" my monthly spending and be more likely to deny a credit limit increase?

For context, I have a 747 credit score, 20m, and I value the future credit line increase more than the 1.5% cash back I would get with the QS.

Edit: I could also upgrade this to the Venture One, but I already have that cars, and it makes no sense to have 2...