DC-10 Question (about circuit versions)

[nosajwp]

Right now, I can think of 3 different versions that I have seen for the DC-10:

earliest: plastic toggle switches, no 60/100 watt switch
middle: metal toggle switches, no 60/100 watt switch
latest: metal toggle switches with 60/100 watt switch

Does anyone know if the 60/100 watt switch was the only circuit change from the middle version to the latest version, or was anything else in the circuit changed at that time?

As a side note...does anyone here actually use the 60/100 watt switch? I know when I had my DC-10, it didn't do much.

 

[nosajwp]

Anyone?

 

[Monsta-Tone]

I never use it. All it seems to do for me is toss out the headroom.

I don't think my DC-10 even has it, but then again, I never went looking for it.