Doing some more testing.
I have merged the output of 4 Bronze Steam Turbines with Invar innards. Each turbine outputs 32 RU/t, merged into an axle carrying 32 RU/t * 4 power.
The Tachometer shows 128 RU/t, and you can see the splits in this picture. The tachometer than displays total RU (RU * power).
