Reciting Korbanos

In the first chapter of Shulhan Arukh, Orah Hayim (1:4-9), the author that "it is good" to recite daily specific biblical passages about the Temple sacrifices. He explains in his Beis Yosef that the source for this practice is the following Gemara (Megillah 31b):

Avraham our forefather said to God: What if Israel sins before You, will You do to them like You did to the generations of the Flood and the Dispersion? He replied: No. He said to Him: "How will I know" (Gen. 15:8)? He said to him: "Bring me a heifer three years old..." (Gen. 15:9). He said to Him: That applies to when there is a Temple standing [and sacrifices can be brought], but what will happen to them when there is no Temple standing? He said to him: I already arranged for them the order of [the passages] of sacrifices. Whenever they read them, I look upon them as if they had brought before Me sacrifices and I forgive all of their sins.

From this Talmudic passage, we see that when sacrifices cannot be brought and we read the Torah passages about those sacrifices, it is as if we had brought them. For this reason, Rabbenu Yonah even goes so far as to say that we are biblically obligated to recite the passage of the daily Tamid sacrifice just like, if the Temple were standing, we would be obligated to bring the Tamid.

R. Tzvi Pesah Frank (Responsa Har Tzvi, Orah Hayim 1) points out that reciting the passage is not literally as if one had brought the actual sacrifice. When the Temple is rebuilt, one will still have to bring the sin-offerings for which one is liable even if one had already read the passages. This is explicit in Shabbos 12b:

R. Yishmael ben Elisha said: I will read (on Shabbos using an oil lamp) and will not move [the candle]. One time, he read and went to move the candle... R. Nassan said: He read and moved it, and wrote in his notebook: I, Yishmael ben Elisha, read and moved a candle on Shabbos. When the Temple is rebuilt I will bring a fat sin-offering.

If reading the Torah passage about a sin-offering is like bringing a sacrifice, why did he not merely read the passage? Clearly, then, reading the passage is not the equivalent and is only a way of delaying God's wrath until a sacrifice can be brought.