MSDN ISO With SP1 does not allow the install or April 2015 CU

[SPStuff]

Hi Brian.
I fought with this issue for a few hours today :-(
I haven't read this blog post :
https://blogs.technet.microsoft.com/stefan_gossner/2015/04/14/common-issue-april-2015-fixes-for-sharepoint-2013-might-not-install-on-sharepoint-2013-sp1-slipstream-builds/

In fact The MSDN ISO was not re-released and the this ISO, although it is slipstreamed with the good SP1 version, does not allow the installation of the April 2015 CUs.

Not sure you can add a condition to the script as the versions of the installer are the same. maybe a NOTE or Warning about the ISO origin of the ISO.

The issue is the download and slipstream went well but the install only installed the base MSDN SP1 binaries.