"SoftLayer_" prefix removed for readability.
The profile preferences are an aggregation of the default preferences and the customized preferences.
For each SoftLayer_Layout_Profile_Containers on a SoftLayer_Layout_Profile, the SoftLayer_Layout_Preference are inherited through the profile preferences. However, any one of these may be overridden through the [[SoftLayer_Layout_Profile::modifyPreference()]] method. Rather than maintaining two different sets of preferences, all preferences are grouped together through the profile preferences, presenting the customized preferences in place of the default preferences they are overriding.