I'm noticing that once a release goes out of print in the 12k shop, if copies of that release are replenished (e.g. sent back, found, etc.) the price goes up. For example, I purchased my copy of Sawako for $14, but now that it's gone out of print and has since resurfaced in the 12k store, you must pay $27 for it. Can someone please explain why this has happened?