What I understood is that, when ever we say LO System reqd. as per API 614 Chapter-2, It means Both Chapter-1 + Chapter 2 are applicable.
Same way for Chapter-3 Lube oil system - Chapter 1 + Chapter 3 is applicable.
Means, Chapter-1, that is General details for Lube oil system are to be consider with either chapter 2 or 3 or 4.
Is my understand is correct.