There's a thing going on
There's a thing going on among Reformed academic theologians regarding the republication of the Covenant of Works at Sinai. Because they never saw the simplicity of it, that Jesus came to fulfill what Adam failed to fulfill, and that Jesus was born under the law, and that that law was republished in obviously elaborated form on Sinai (what, was Jesus supposed to not eat of the Tree of the Knowledge of Good and Evil? and no the battle in the desert with Satan was not a direct analogue to Jesus fulfilling the Covenant of Works), and Jesus followed that law dotting every 'i' and crossing every 't.'
That simplicity which was missed by Reformed academic theologians who solely concentrated on how a republished Covenant of Works could relate to fallen human beings called national Israel, never seeing them as a type of the Messiah who existed to bring the Messiah in their midst in the fulness of time, the Messiah who *could* fulfill the Covenant of Works, etc.
Because they missed this they are now saying: "Well, ahem, of course, it's not as simple, uh, as to just say Jesus fulfilled what Adam failed to fulfill and that the law at Sinai represented that Covenant in the Garden and, uh, so on. It's much more complicated than that."
In other words Reformed academic theologians are reacting to protect their vanity by 'complicating' the matter and by that hoping to lasso it back in to their sterile professor's lounge and away from the street Calvinists who tend to see the parts in relation to the whole upon their first effort to see the parts in relation to the whole, and then recognize terminal understanding of biblical doctrine when they reach it. Rather than making everything akin to ever learning never able to come to understanding of the truth.