Cannot extend storage pool volume in Server 2012

[SirEvan]

My coworker and I set up server 2012 standard on a machine here at work to start testing software against, and ran into a problem with trying to use storage pools. When creating an array, everything is fine (3 drive parity). However, when we try to add a same-size disk to the volume and expand it (much as you'd do on a hardware RAID controller), it gives the attached error. Looking on technet forums, the storage pool docs say that it is recommended to add drives to a pool in increments of the column size...in this case 3...is that really necessary? Searching on google has not yielded much information on this error. We've assumed that you should just be able to extend a volume one drive at a time, much as you could with windows home server and/or a hardware raid controller.

[Eversurf]

What size disk do you currently have and what size are you looking to move to? Are you on BIOS or UFI?

[cybertimber2008]

What size disk do you currently have and what size are you looking to move to? Are you on BIOS or UFI?

I'm not familiar with 2012 yet, but looking at the bottom right corner of the screenshot, it looks like they are all 2TB drives, and the current capacity (before the expansion) is 3.63TB