So have two e-editions with two prices, one that comes out early with the hardbacks and includes something extra... an additional short story, visual media, lack of DRM, whatever, and one that comes out later with just the main text. Or... just drop the price of the ebook when the softback comes out.
Price elasticity of demand curves are just that—curves, so dropping the price below $9.99 doesn't mean revenue will continue to grow. However, I won't buy their claims until I see their curve, and I bet it supports that dropping the price to $8.99 or even $7.99 increases revenue even further.
How many think that paying ten dollars for something for which the marginal cost is nearly zero is rather absurd? Virtually free replication is something for which capitalism is not well suited, hence all the manufactured scarcity we see.
Remember, UNIX spelled backwards is XINU. -- Mt.