I do commercial/industrial work almost exclusively, (except some ultra custom homes) Any method I'd use for figuring residential would be non-competitive overkill at best
(but I'm always willing to learn)
Nearly everything here has the lights and recps run on different circuits, though.
In CA, our commercial lighting loads are limited by our energy laws. An office is generally only allowed 1.6 watts per square foot, so to use the NEC's figure wouldn't be practical.