According to her, she does it so that she can write in two different styles without people getting upset at not getting what the expected.

Huh. The story I heard, and frankly I believe it more, is that Megan Lindholm was only selling moderately, and she had to change her name in order to start with a clean slate, order-wise. IIRC, bookstores usually will only order the number of books you actually sold on the last round, minus some percentage. As a result, unless you have a big breakthrough, you're trapped in a slow downward spiral with regards to sales. "Robin Hobb" came with no history, and therefore there was no reluctance on booksellers' parts to order plenty.