The problem with complex terms and phrases is that sometimes, oftentimes, people use the same words to mean entirely different things. And this gets worse when it comes to neologisms or even technical jargon that have different meanings in different fields, i.e. "analogy." Much misunderstanding could have been avoided if the parties involves would actually try to understand the other party and how he is using terms and what he means by these terms, instead of jumping to (false) conclusions about what his opponent actually holds to.
In the case of the phrase "eternal functional subordination" or "eternal functional submission," the phrase by itself seems to have a rather straightforward meaning. First, by "eternal" it refers to something that is true that extends from from eternity past to eternity future. Second, by "functional," it is understood that it pertains to doings, works and roles. Third, by "subordination" or "submission" it means one party being lower than the other party in some sense. Putting them together, it seems clear that the combined phrase must have a reference to works and roles, and thus the economic sphere, of the Triune God from eternity past to eternity future. By definition of the word "functional," any type of ontology must be ruled out. To claim an "eternal ontological functional submission" makes as much sense as a "round square" or "square circle," that is, an oxymoron, a logical contradiction.
Thus, it comes to me as an astonishment that many people evidently don't even think through the meaning of the words used to constitute the phrase. Others see the word "eternal" and immediately think of God's essential attribute of being eternal, as if that is the only way we are to understand the word "eternal." It does come as a shock how many take the phrase without thinking about its meaning, and then assign it a meaning based upon what they think the EFS/ ERAS proponents are teaching. One might as well call the position ABC or XYZ and the net effect would have been the same.
It is really sobering to see how people are so careless in discussing theology even among those who should know better. And here I am not talking about the critics only but everyone. The only reason the critics have material to criticize is because those who promote EFS/ ERAS have been sloppy with their language. Both sides by and large are filled with those who refuse to understand the other side and insist on using their terms to criticize the other side, whether intentionally or unintentionally is besides the point here. It may be that either side have people whose paradigm of thought is so rigid that they are unable to properly assess anything that falls outside their paradigm. Regardless, the result is the same: People from either side insisting on interpreting what the other side writes in line with their own paradigm of thought, and refusing authorial intent for all intents and purposes.
Since the words that constitute the phrase "eternal functional submission," and the way they are put together, sound perfectly orthodox, I see no reason why we should not interpret it according to its constituent parts and the relations between them. It should be also natural that the orthodox meaning is the default meaning whenever one sees the phrase being used, unless it can be proven that the writer is using it differently.
Eternal Functional Submission therefore speaks about the economic submission of the Son from eternity past to the Father. We in the Reformed tradition affirm it in the Pactum Salutis, and therefore, for all intents and purposes, EFS is Reformed.