I think we are because I would focus on that fragment where Epicurus is reliably (it appears) quoted as criticizing those who walk around harping uselessly on the meaning of the word good.
I think that's Plutarch and maybe that's a fragment that would be well worth our examining the Greek in detail.
You know the one I mean? I need a better way to lock down the source but it appears to be;
QuotePlutarch, That Epicurus actually makes a pleasant life impossible, 7, p. 1091A: Not only is the basis that they assume for the pleasurable life untrustworthy and insecure, it is quite trivial and paltry as well, inasmuch as their “thing delighted” – their good – is an escape from ills, and they say that they can conceive of no other, and indeed that our nature has no place at all in which to put its good except the place left when its evil is expelled. … Epicurus too makes a similar statement to the effect that the good is a thing that arises out of your very escape from evil and from your memory and reflection and gratitude that this has happened to you. His words are these: “That which produces a jubilation unsurpassed is the nature of good, if you apply your mind rightly and then stand firm and do not stroll about {a jibe at the Peripatetics}, prating meaninglessly about the good.”
This is an area where I think it is understandable why Cicero framed Torquatus' argument in the way he did, but I question whether Epicurus would fully endorse that interpretation, especially since Torquatus himself seems to be saying that he disagreed with Epicurus.
Those are two sources I would compare and contrast as a way to getting to this issue of the "highest good" problem -- and of course I also think deWitt's points on this are worth incorporating as to multiple meanings of the word good and how "highest" might not be the best way to look at things (at least without lots of explanation ) and --- that need for explanation -- is exactly the problem of "concepts not mapping to feelings' that we are talking about.