Rav Breitowitz: Shavuot and Why Moshe Asked for an Extra Day

According to the Magen Avraham's explanation, Hashem did not give the 10 Commandments on Shavuot. Hashem gave the 10 Commandments the day after Shavuot, but Shavuot was the day that God would have given had Moshe not added an extra day of preparation on his own. What is the Magen Avraham's idea? We celebrate Shavuot on the day that God planned to give the Torah, which would have been the 50th day of the Omer, and not on the [clears throat] actual day that God gave the Torah, which is day 51. This is the Magen Avraham's chiddush based on the calculation of the Jews leaving Egypt Thursday and the Torah being given on Shabbat. So, the question that we want to explore a little bit is why should the hypothetical be more significant than the actual? Meaning, why would I celebrate the holiday of Matan Torah on the day that God would have given the Torah instead of the day that Hashem actually gave the Torah? Shouldn't the actual be more important than the hypothetical?