I agree that the publisher is kidding themselves to think that this is going to delay distribution of the ebook version by much-- and will possibly prompt "pirates" to get the rest of the book out on the darknet even earlier, just for the added "gift economy prestige points." (You'd think the publishers would have taken note after the
Deathly Hallows fiasco.)
If they've got the ebook version ready to go at the same time as the hardcover-- and I see no good reason why they should not-- it should go out at the same time. Or earlier-- why wait to start letting the book earn money and generate buzz? Premium-priced eARCs (Advance Reader Copies) are fine, but the regular ebook price should reflect the lower production cost, though they could try to keep the profit margin similar to hardcovers for the first year if they're really worried about hardcover customers going with the ebook version instead (I wish we actually had that problem to worry about
), with a suitably discounted price once the paperback version becomes available.