RG 80-112 SC wattage issue

[Led Hendriani]

Unlike all of the other RG 80 amps I see on the internet that say:
80 watts with one 8ohm spkr and 100 watts with two 8ohm spkrs (=4ohms)

...on my Oct 1981 amp, it is printed that it is 60 watts for both 8 and 4 ohms.

What is going on here?

Thanks in advance!

 

[Led Hendriani]

I am really hoping it is a typo!

Anyone have the correct procedure for testing this so I can know what the wattage output is for both 4 and 8 ohms?

Thanks!