Regulation of remote bus - any limitations of PSS/e?

edit

I'm trying to understand better PSS/e and I wonder are there any limitations related to definition of regulation

a) case a. for example is it problematic for PSS/e to handler regulation of the same bus with two generators connected directly to the same bus (implicit modeling approach)?

b) case b. Generator is connected through step up transformer equipped with tap changer (explicit modeling approach) indication both the same remote bus of station B.

c) are there any other limitations that you have encountered while modeling (related to indicated bus for regulation)?

d) do you practice to simplify modeling for some reason and point to different place then in reality?

e) is there any limitation how far remote bus can be?