BIJ are the same as most Japanese retailers, outside of HLJ. They, in general, don't accept them, but I've heard they will do it once or twice. Don't abuse it, though.
The more I look at the size dimensions for Mikasa, the more I think I might pass on her. She seems to be pretty small being only 17cm, which is the same as GSC's Inori [who I was incredibly disappointed with]. Even the regular version of Madoka, who's a little girl, was 19cm, and they're both 1/8 scale. Given the amount of detail in this one, everything is likely to be super-small. Sure, with the roof base it'll appear larger than it is, but the actual figure won't be.
Perhaps I'm just looking for reasons to not order her, and it's working. Somewhat.