I would guess that a standard Edison Base lampholder marked "Max 60 Watts" is the rating only for incandescent lamps. How that translates to CFL or LED's is not (yet) defined by the NEC.
If the lampholder's marked "Maximum 60 Watts", you can put up to a 60-watt bulb in it, regardless of what kind of bulb it is. That said, it only assures that the lampholder won't overheat. A CFL or LED bulb might overheat and quit working. (but won't overheat and create a fire hazard)
These are
actual watts, not "equivalent" watts. "Equivalent watts" are nonsense.
However much actual power a bulb consumes is very nearly equal to the amount of heat it dissipates. Even "high-efficiency" CFLs and LEDs convert very little of the input power into visible light.
The confusion started when the marketing people assumed that the American public is too lazy or too stupid to distinguish between the amount of electricity a bulb consumes and the amount of light it emits. They labeled 15-watt CFLs "60 watt" because they emit the same amount of light as the 60-watt incandescents they replaced.
Of course, anybody who graduated from a decent high school knows that a watt is a unit of power, not a unit of luminous flux, and the confusion-free method would have been to label them "15 watt" and "900 lumens".
It doesn't need to be separately defined by the NEC. The lampholder has a limitation and the NEC requires you to abide by every device's limitations.