The accepted definition of base is 'the fundamental principle or underlying concept of a system or theory; a basis'; differentiated features refers to optional add-ons such as FM receiver, voice control, scroll control vs buttons only, color vs monochrome display, hard disc size/form factor, etc. The English language can only be interpreted to a certain degree; IMHO, going beyond that merely confirms that the interpreter's reach has exceeded his grasp.
Always tell the truth. Then you'll never have to remember what you said the last time.