That is NOT a series type R/R but simply a MOSFET based shunting R/R.
It will help with problems of the R/R failing that some bikes have, e.g. if it can't handle the load of dissipating all the heat. But it will not help in our case, and might even make things worse. The MOSFET type shunting regulators run cooler than their thyristor counterparts because of their construction, which increases efficiency. But if you are not using the extra electrical power, and it's not being converted to heat in the R/R, the only way where it can go is the stator (and to a minor degree the wiring)!