Read an eBook Week Becomes a Feeding Frenzy

At least, if my own experience is anything to go by!
I mentioned the other day that the few books I've self-published have been available for free on Smashwords to celebrate Read an eBook Week. Well, the week is almost up and it has been an astonishing success. People picked up almost as many of my self-published books in this single week as they did in the whole of the past year! If this pattern is reflected across all participating authors, this is going to be an outstanding success for Read an eBook Week.
There are five books of mine involved in the celebration – only two of them under my own name – and it is just as fascinating as the overall numbers to note that the three written under a pseudonym have been flying off the virtual shelf at ten times the rate of the ones under my own name. I would dearly love to know why that is because,
The pseudonymous books are in a different genre to the one I normally write in. Is that genre ten times more popular than sci-fi? (Maybe I should be asking, are there any genres that are not ten times more popular than sci-fi?)
The general consensus among those I trust to read and comment on my books before I submit them anywhere, is that the pseudonymous books are nowhere near as good as my sci-fi books. They tell me I should stop dabbling in other genres and stick to the knitting. That's why they're self-published under a pseudonym in the first place – I have no intention of inflicting them on a publisher but I can't bear the thought of them just sitting on my hard drive. Could my beta readers be wrong?
I made a couple of announcements about my books being available free for RaEW, here and on Twitter, but anybody who noticed would only be able to find the ones under my real name, not my pseudonym. That means the pseudonymous books got absolutely zero publicity and yet are going ten times faster than the ones that did! What does this tell me about book marketing? Does it mean some genres require a hard sell, while, for others, there are crowds of eager readers prowling the book sites, desperate for free books?
Since a week of free is roughly equivalent to a year at next-to-nothing (most of my books are normally for sale at $0.99) I'd like to be able to conclude something about the optimum price-point for self-published ebooks. It certainly looks as if I can. Basically, if a self-published ebook is not free, I can expect to ship about a fiftieth of the book's potential numbers. So, do I want lots of readers, or a trickle of income? It does seem to be an either/or situation.
There are lots of questions a result like this raises, but I think those are the big ones for me. Is anyone else seeing this kind of thing with free vs sold books? Is the picture as depressing as it looks? I mean, it's great that Read an eBook Week is looking like a huge success, but the sudden voracious consumption of my work, just because it's free, leaves me with a slightly queasy feeling – like I'm watching a joint of meat being devoured by piranha fish.

Is this the face of today's ebook reader?