changing block size on database disk

Hi,

I have an request from an application demand vendor sighting this below MS link :

http://technet.microsoft.com/en-us/library/dd758814(v=sql.100).aspx

The vendor is asking me why this practice was not followed when we are dealing with 2008R2 SQL server on windows 2008R2.

The understanding is this change from 4KB to 64KB block size will very much be helpful to reduce the I/O and so we are going to have the same actioned.

Now normally we always have our SQL installed on the given disk that comes default with 4KB block size, is there any installation document from MS site that it states we really have to use only 64KB block size disk for SQL and not 4KB disk, installing the 4KB disk is forbidden by Microsoft ? etc

Help is very much appreciated

Regards

Eben