Do you?
Actually, the Church has changed it's doctrine on the atonement. All one has to do is look up "Atonement" on New Advent (the Catholic encyclopedia) and it will even tell you the view has changed. Catholics no long believe Christ was a sacrifice to a wrathful God. This is old school. Rather Catholics believe Christ set an example. Very Orthodox in view but never what the western fathers taught.
You'll also find that Augustine wrote about the confusion of the purpose of baptism. At first they thought that once baptized you would live a perfect life. When that didn't work then they taught when you were baptized it was up to you to live a perfect life. Oops, that didn't work either. Then the Church taught that you should wait until the very last possible moment and be baptist so you wouldn't sin. Trouble with this approach was that there were some baptizers who just weren't fast enough runners. Finally they looked upon baptism as an act of faith. I say all of this just to illustrate that the early fathers didn't have a handle on everything.
As far as the Eucharist goes, Christ is present wherever two or more are GATHERED in His name. Wouldn't you agree? Grace is not imparted through the Eucharist. We know we have received grace because we believe in Christ Jesus.