No, that's not what I have been saying at all.
I meant that the theory of free election and rejection which Paul develops from chapter 9 on is not applied to the eternal / final fate of anybody (Calvin's mistake), but to the "historical" and "provisional" fall/rejection of "Israel" (with the exception of a "remnant") and subsequent election of the Gentiles, which are still both subject to change (this is precisely the point of v. 11ff: those who have been "broken off" can still be "grafted in," et vice versa).
Now the final "happy ending" (the "mystery" by which both "all Israel" and the "fulness of Gentiles" are to be saved, v. 25ff) goes beyond this: the "all" who have experienced disobedience and will be shown mercy at this point exceeds the present number of "believers," both Jews (the "remnant") and Gentiles (those who now believe). This is what I have called a "universal horizon" -- if not a positive confession of universalism.
Were the "all" just two categories as Calvin has it, it would already be fulfilled by the current "remnant" of Israel and Gentile believers. There would be no need for a further "mystery" moving it to a broader scale of fulfillment.