The admonition here in Parshas Ki Savo contains ninety eight curses, whereas the admonition in Parshas Bechukosai contains half that amount, forty nine curses.
The inner reason for this distinction lies in the fact that the curses of the admonition are not intended as mere punishments, but rather as “blessings in disguise,” which spiritually purge and refine a person, making him a fitting receptacle for even greater blessings from God.
The admonition of Parshas Bechukosai, which is read before Shavuos, is a spiritual preparation which enables a person to embrace the giving of the Torah anew, which occurs every Shavuos. Theadmon ition of our Parsha, which is read shortly before Rosh Hashanah and Yom Kippur, prepares us for the High Holidays.
This is the inner reason why there are more curses here in Parshas Ki Savo—for on Shavuos, when the Jewish people receive the Torah, they are on the level of tzadikim (righteous people). But on Rosh Hashanah and Yom Kippur, where the key emphasis is on man’s effort to return to God, we reach the level of ba’alei teshuvah (penitents). And since the ba’al teshuvah is so much higher than the tzadik, many more curses (“blessings in disguise”) are read in this Parsha so as to provide the greater spiritual preparation required to reach this sublime level.(Based on Likutei Sichos vol. 2, pp. 392-3)