Section 90.7 requires the inspector to judge suitability of an installation based upon the listing of the equipment and the installer's adherence to the instructions that accompany a listed product. In other words: instructions must be followed.
Conductors and wiring lugs are listed, and therefore must be installed according to that listing. The instructions will typically require stripping the insulation to a minimum exposed comnductor, sometimes a termination compound and sometimes a torquing range for the connection.
Also, Article 110.14(A) requires "Connection of conductors to terminal parts shall ensure a thoroughly good connection without damaging the conductors..."./
All of which means most inspectors will interpret that all the wire strands need to be under the same lug, as lugs are rated for a particular wire size, not for some of the strands.
