Taking exception with your argument, as well as laying aside the usual (valid) argument re the "wine" of the communion table that MHG presents, let me relate this experience:
I once partook of the tokens of the Lord's Passion in a Lutheran ritual at my cousin's church. What stunned me was that the wine was not in reality even symbolic of Jesus' Blood; it was, in fact, alcoholic wine of the kind reminding me of my pre-saved past as a habitual heavy drinker!
Now, you know that a fluid containing some ten to twelve per cent of ethanol cannot possibly be even representative of the life-giving blood of any human or beast. The reason that you don't know how table wine can become "the real blood of Christ" is that it isn't, and there is no possible explanation how in God's created universe that it ever could be, literally or figuratively.
It is true that human blood can contain a bit of unmetabolized alcohol (click here), but even one half per cent BAC would be lethal.
To me, this is sufficient logical and experiential evidence that some Lutheran wine (I found out afterward that on the communion card one may indicate a choice for non-alcoholic) cannot even symbolically represent the state of human blood. With this in mind, I do not hold your interpretation of 1 Cor. 11:27 as having any validity whatsoever.
Nor would Jesus ever have His disciples, now quite well aware of symbolism in His teaching, ever come to the conclusion that their table wine (alcoholic or not, and I think not) could ever be in plain literal language the same substance as His literal blood, still wholly contained within His skin, and not yet exsanguinated at Calvary.
I take exception to YOUR exception.
Scripture states clearly that it is both.
Therefore, because Jesus rose from the dead, and he laid his stamp of approval on it, being, you know, GOD, I believe it.
Don’t ask me how it’s true because I don’t know; I only know it is.
"Who, but the devil, has granted such license of wresting the words of the holy Scripture? Who ever read in the Scriptures, that my body is the same as the sign of my body? or, that is is the same as it signifies? What language in the world ever spoke so? It is only then the devil, that imposes upon us by these fanatical men. Not one of the Fathers of the Church, though so numerous, ever spoke as the Sacramentarians:not one of them ever said, It is only bread and wine; or, the body and blood of Christ is not there present.
Surely, it is not credible, nor possible, since they often speak, and repeat their sentiments, that they should never (if they thought so) not so much as once, say, or let slip these words: It is bread only; or the body of Christ is not there, especially it being of great importance, that men should not be deceived. Certainly, in so many Fathers, and in so many writings, the negative might at least be found in one of them, had they thought the body and blood of Christ were not really present: but they are all of them unanimous.”
–Luther’s Collected Works, Wittenburg Edition, no. 7 p, 391