No, a HO stator only increases it's total capacity or capability if you prefer. The R/R regulates at what voltage level the charging system will charge to. At low (idle) RPM's there is not enough input from the stator for the R/R to reach it's maximum output, but as you increase RPM's the stator finally supplies enough input to the R/R for it to reach it's saturation. Once you reach that point, the R/R will not produce any higher voltage regardless of how many more RPM's you go to. The excess output from the stator is shunted to ground in essence.
Now, as the load on the battery increases, the more energy the R/R has to supply. So, with a small load on the battery you may reach the maximum voltage output at say arbitrarily 3000 RPM, but if you then switch on your driving lights, turn the radio up real loud, and honk your air horn all together, there is a bigger demand on the battery so the R/R output will seem to drop at the same RPM. But if you increase your rev's the output will eventually reach it's maximum, but it will be at say maybe 4500 RPM...