Yeah, I assume that you can just have a non-deterministic expansion which will add some entropy per word to increase the entropy of the passphrase over the abbr

Yeah, I assume that you can just have a non-deterministic expansion which will add some entropy per word to increase the entropy of the passphrase over the abbreviated version, but my point was just that even if there's no increase in security by using the full passphrase, counter-intuitively, using the full phrase would likely be more convenient for me (and probably for many others).