rules settings between 2 articles

Someone help me to understand difference between rules settings between 2 articles. I noticed only local Admin password mentioned in Microsoft & not sure about WinPEScratch space size to 128& other settings

http://www.scconfigmgr.com/2013/09/19/create-a-windows-8-1-enterprise-reference-image-with-mdt-2013/

http://technet.microsoft.com/en-us/library/dn744290.aspx