CICS Install job DFHCOMDS should allocate DFHCSD with secondary extents

The CICS installation process only allocates a primary
space for the DFHCSD in the DFHCOMDS job which creates the
DFHCSD dataset.

Looking back it seems this has been the case for some time.
I looked at the 5.3 DFHCOMDS job, and can see it still does
the same thing:
DEF CLUSTER(NAME(@dsindex@.DFHCSD) -
IXD -
REC(12000)-
RECORDSIZE(200 2000)-
FREESPACE(5 5)-
VOLUME(@dsvol@) SHR(2)) -
.
The CICS TS 4.2 doc and the 5.3 doc both contain a section:
Initializing the CSD
For the 4.2 kc, see url:
http://www.ibm.com/support/knowledgecenter/SSGMCP_4.2.0/com.ib
m.cics.ts.doc/dfha2/topics/dfha2_initialize_csd.html
.
This section: "Initializing the CSD"
has a subsection entitled: Creating a larger CSD
That tells customers
"To avoid the CSD filling while CICS is running, ensure that
you define the data set with primary and secondary space
parameters, and that there is sufficient DASD space available
for secondary extents."
.
So looks like we are not following our own advice.
This is probably the same for all versions.