Dynamic Pool expansion

Hi everyone, I'm reading stuff about Dynamic pool configuration and expansion in here: https://support.emc.com/docu85573_Dell-EMC-Unity:-Dynamic-Pools---Overview.pdf?language=en_US, but there are few questions that I have about the expansion of my pool. I already have 17 SSD 3.4TB disks in a RAID 5 (12+1) configuration These are my questions: What happens if I add 1, 2 or 6 drives to the pool, I mean what happen with the space? What happens if I add more than 15 drives to these pool? What is happening with the 3 extra drives in this 17 drive array? because I understand the (12+1) uses 14 disks. I will appreciate any help!