Storage Spaces Bad Issues!

Hi, I've recently bought "Windows 8 Home Server Step by Step" then I followed this guide to migrate my WHS v1 data to the new Storage Spaces environment.

Since I did not bought new HDs I had to plan step by step data moving as follows:

1) Start

WHS v1 Pool: 8,1Tb of data into 11x2Tb HDs with Folder Duplication Enabled

2) Disabled Folder Duplication

3) Removed (one by one) 5 HDs from the WHS v1 Poll consolidating the data on the remaining 6 HDs

4) SetUp on the Win8 machine a Storage Pool with the 5 HDs and on it a Storage Space with parity, default porposed size of 6,50Tb

5) Moved from WHS v1 to Storage Spaces data until SS warned me of adding 3 disks (usually when at least 3 HDs of the pool past 70% of used phicial space)

6) Removed 3 mode HDs consolidating data from the WHS v1.

7) Added the 3 HDs to the Storage Pool and expanded the Storage Space size to 14Tb

8) Finished moving data from WHS v1 to Win8 SS

9) Removed the last now empty 3 HDs from WHS v1, added to the Win8 Storage Pool

Now in the Win8 I have the 11x2Tb HDs of a phisical total rela space of approx 20Tb but I cannot expand the Storage Space over 15,99999999!
But, and now the mistery becomes even more weird, if I create a new Storage Space in the Storage Pool I'm be able to create it with the size of 63TB!
Why?