Nelson Pass is the Class-A master, and he says the Inter 60 has 30w-8ohms of Class-A on it and he uses that size of "external" heat sinks for it to dissipate that heat, and they do run very hot.
Then the smaller "internal" heatsinks of the Lux are not dissipating the same amount of Class-A, especially "if" the Class-B wattage into 8ohms is even higher than the Pass Int-60
Things don’t add up with the Lux Class-A figure presented or the Class-B wattage.
The higher the rail volts for higher Class-B claimed, then "for the same Class-A bias(30w)", the heat dissipation goes up exponentially.
Cheers George