Copy from All
Once you have created a report template that can be used for all vendor products for the enterprise object (a heterogeneous template), you then can use the feature to create a vendor-specific (homogeneous) version of this template, using the same fields that you've already selected and configured. Then, you can add vendor-specific fields to the new report template.
The Copy from All operation overwrites your homogeneous configuration, so if you modify this once and copy from all again, it will overwrite any modifications you've made. Also, you cannot go in the reverse direction--vendor-specific template to a heterogeneous, "all vendor products" template.
Note:
There are cases for the Array enterprise object where Copy from All does not work. For example, a heterogeneous report template (a template representing all vendor products) may have a LUN object, but the vendor of the destination report template may not have that LUN object.