It looks like the Vatican Sayings show simplified versions (or with a more common language in some cases) of some Principal Doctrines.
I share a comment that can be interesting from Enrique Álvarez' dissertation:
"In both cases [PD 5 and VS 5], we can see how the genre of the florilegium is effective in the transmission of doctrine at the price of rounding off and simplifying the contents. Thus, PD 5 has become an effective aphorism that is a reminder of the reciprocal implication of pleasure and virtue.
Indeed, we understand that "this" (τοῦτο) in the last sentence refers to the doctrine taught by both members of the biconditional: if there is no pleasure there is no virtue and if there is no virtue there is no pleasure. As for SV5, we interpret that the compiler's purpose has been to express the Epicurean doctrine in the form of a simple argument having the form of the modus ponens, in this case, with negative premises: if one does not live with virtue, one does not live with pleasure; one does not live with virtue, therefore, one does not live with pleasure. τοῦτο, at the end of SV5 takes up the protasis of the first premise of the modus ponens, that is, sentence P of the form of reasoning: P then Q, and P; therefore Q." (El Gnomologium Vaticanum y la filosofía de Epicuro, 2016, p. 212)