Can't say anything about the Rossi, haven't riden that one so I concentrate on the Flagship.
I've riden the 2013 Flagship the entire season in all types of conditions and I think, this isn't the board you're looking for. I love the board for pow days and on morning groomers. It's very (very, very!) stiff, longitudionally and torsionally. Positive: you get immediate response, its absolutely stable at high speeds. It's fun to carve in freshly groomed slopes. It's more fun to straight line and it's pure heaven in powder.
Negative: It's hard work in copped up afternoon groomers cause of the stiffness and lack of dampening. All bumps will be transferred to you without absorption. You have to be down in your knees to absorb this bumps all the time, no chance to take it easy, ever.
And for jumps? Not much pop there. Its a kitchen door. Fun if you hit natural stuff with a soft powder landing. But on groomer, the landing will be pretty rough.
Have a look at the Ride Highlife or Burton Custom X. Both stiffer than your Flow and better absorption than the Flagship. Both excellent carvers and suitable for jumps (I'm not an expert in jumps, hope someone with more expertise will chime in)