Well, if I were you, being a boob man, I would fight like hell to prevent her from downsizing.
Unfortunately, you hear that story pretty often. I'm guessing that she initially chose to honour your request for bigger boobs, but somewhat reluctantly. Does she, like many other women, enhanced or not, think deep down that big tits indicate bimbo-like status with no brains, and a predisposition to the negative stereotype of an excessively liberal sexual attitude?
I'd like to know how many women really, personally, like big breasts . . . and how many are doing it for outside reasons. Sure, big tits make you money if you're in the entertainment industry. From there, I think many women do it to attract a man before marriage and keep a man after marriage. But I don't believe, unfortunately, that there are many woman who would act to excessively enhance their busts primarily on their own accord.
Let me ask you something, with respect . . . if it wasn't for you, and your love of big boobs, would she choose to downsize further than the 1400cc; perhaps even to 800cc or less? I think convincing their women otherwise is where the real battle for many boob men lies . . .