P9 SFF-3 SSD features for i

I was re-evaluating the various P9 SFF-3 SSD features for i.
I'm in the process of obtaining maintenance numbers for when the 3yr warranty expires.

I came up with the list below.
I'm a bit confused with the August 7 118-061 announcement.
http://www-01.ibm.com/common/ssi/ShowDoc.wss?docURL=/common/ssi/rep_ca/1/897/ENUS118-061/index.html&lang=en&request_locale=en

Some of the sizes already existed for the same size.
Why are there two different features for the same drive size?
Also, did I omit any?
Is there an easy way to see/determine all the valid SSD features available for a particular P9?

Enterprise Price Maint.
ES8R 775GB SFF3 SSD 4K FOR IBM 4,199 ???
ES8W 1.55TB SFF3 SSD 4K FOR IBM 7,999

Mainstream
ES84 931GB MAINSTREAM SAS 4K SS 2,275
ES93 1.86TB MAINSTREAM SAS 4K S 4,275
ESE2 3.72TB MAINSTREAM SAS 4K S 7,575

From August 7 announcement -

ESHT 931GB Mainstream SAS 4k SSD 2,225
ESHV 1.86TB Mainstream SAS 4k SSD 3,999
ESMR 3.72TB Mainstream SAS 4k SSD 6,799
ESHW 7.45TB Mainstream SAS 4k SSD 14,999

Thank You
_____
Paul Steinmetz
IBM i Systems Administrator

Pencor Services, Inc.
462 Delaware Ave
Palmerton Pa 18071

610-826-9117 work
610-826-9188 fax
610-349-0913 cell
610-377-6012 home

psteinmetz@xxxxxxxxxx
http://www.pencor.com/