All of the above is correct. However, since you are still understandably having a tough time with this, I will approach it from another direction. When Christ offered the New Testament in His Blood in the cup at the last supper, it is the blood which "is shed," "is" being the continuous present. In Protestantism you were used to the word "sacrifice" being used as a verb, or, in noun form, as a thing performed. In Old testament terms, if we were to say "the sacrifice was immolated," the "sacrifice" is the lamb, the act is the offering and immolation of the sacrifice. Thus, the "Sacrifice" on Calvary/Golgotha refers not to an "action that was done," but a Person--the Lamb of God who offered up His Body and Blood.
But the passages in question themselves tell us this. Hebrews 10.10 states that the offering of Christ’s Body took place “once for all.” Then in verse 12 states: “But He, having offered one sacrifice for sins for all time, sat down at the right hand of God.” The “single sacrifice,” of course, is not a “thing done” as Protestants tend to read it, but rather, as it says in verse 10, is Christ’s own Body. Therefore, one cannot say that Christ’s Body is made present and at the same time say that the “single sacrifice” is not made present, because they are one and the same thing, as the very Scriptures in question clearly say. Again, verse 12 clearly says that He offered this Sacrifice (His Body) "for all time." This is clear enough by itself. However, when we look at the original Greek and see the words "eis to dienekes" it becomes more clear. The term "dienekes" only has one meaning, "continuous." "eis to dienekes" means, "continually" or "unto perpetuity"! Thus, the passage itself clearly states that the "Sacrifice" is Christ's Body and that it is offered once "continually." I hope this helps