The traditional considerations for using pen names? A) You were a respected professional in your "day job" and didn't want your fantasy dabbling to detract from your standing; B) publishers, for their own reasons, wanted you to only write one book a year and let you slowly starve; C) your sales had tanked and you needed to ditch yourself; D) you were writing in vastly differently fields and styles and needed a clear distinction so as to not upset fans; E) there was the real possibility that someone would shoot you if they knew who wrote that book.
The mainstream publishing industry wants you to stick to one type of book and easy-to-shelf brand. The advice you get from editors is solely for their convenience--and it makes good business sense, because a single book is hardly worth building a campaign around, because its useful life is too fleeting. But if it's only a mild stretch, you should stick to your own name whenever possible, because ultimately you are your brand, and you should always care more about yourself than you care about the industry, or the industry cares about you. If Stephen King can do It and Misery, The Shining and Dolores Claiborne, and Koontz can do all his stuff, it's perfectly acceptable for you to just write You Books.
Publishers have legitimate logistic reasons for carefully controlling the flow of product, due to inventory issues, bookstore needs, production considerations, and marketing concerns. But in this new digital/POD era, it's actually smarter to have everything out at the same time--there is very little reason to dole out content in measured paces, unless you have a specific gimmick or campaign that requires timing. That's true for authors as well as publishers, though authors have the ability to react more quickly and with less to lose. And your books cross-promote each other, building your brand, which more and more is something that can last a lifetime rather than popping up in three-month bursts in the middle shelves of a bookstore. Be yourself whenever possible, and when you're not, make sure you have a good reason.