I dunno... Just from using my own purchase history, if I was to get even 10% of what I've spent on this game back, while keeping all of my crap, why would I spend more real money?
Take it to 25, 33, 50, 66, 75 or even 100%, there is no need (at least for people like me who have spent tons) to spend one extra red cent, when you've been given a massive amount premium currency for FREE.
I, myself would be enticed to spend money just because they lowered prices.