SSD RAID Volume properties and Array properties

[Hopper642]

I have 2 Intel 520s in RAID 0. There are a couple of things I am unclear on. In Intel IRSTe software, there's Volume properties for my RAIDed drives, and then there's Array properties which appears to be totally different. The volume has about 434G of space, but the array is 457G. And then under array properties, the "available space" is only 22G. ??? Would someone explain this to me. I just don't understand it. Thanks.