dbPhyStart is the same as PHY START in DarkBasic I believe
and so is dbPhyUpdate the same as PHY UPDATE, as far as I know the products are almost exactly the same in functionality being compiled from the same codebase I assume, just one is in a DLL form for the DarkBasic language and the other as a function library for C++.
As to if you should read something, I would say yes, definately lol, its always a good idea to have a look at the reference guide if ur not sure on the usage of a function or what its for, and also with DarkGDK and its addons, you also have the added advantage of being able to look through the header files and check out some of the internal commands that are exposed, and some undocumented functions you may be able to take advantage of as well as the help files
If it ain't broke.... DONT FIX IT !!!