Being in the ebook business is more complicated than I thought. We've had a number of titles that had 56 cents tax, one that had no tax at all. I think the tax rate depends on where you purchase the book, not where you buy the book from.
Our last contact at the ABA said that Wisconsin has a download tax, which is accounting for the extra fees. We're not sure that this is true. That said, if it is, we're going to reimburse everyone who purchased books today before 1:15 Central/2:15 Eastern (either by credit card or check) and pay for the tax ourselves.
After that, the warning is up. More to come later today.
Later today--I've talked to S. at the ABA and he tells us the problem has been fixed. We are putting together a list of folks who were overcharged. Their credit cards will be credited.