This question was posed by one of our revered sages, who are comparable to a town where all the trees and their fruits are beautiful, the faultless sage, our master and teacher Rabbi Yitzhak ben Sahal, may his Rock preserve and vitalize him, concerning a citation from what Maran [Master] Tor Orach Haim [Yaacov ben Asher] said: One does not recite the Blessing on Fragrances at the termination of a Yom Kippur that occurs on Saturday night, the reason being that he has no additional soul [neshama yeterah] because of the fast. This reasoning, however, implies that one who fasts on the Sabbath because of a disturbing dream must refrain from reciting the Blessing on Fragrances at Havdalah, which is peculiar, for this is not common practice.
And I, in all humility, say the custom should be observed, for there is a distinction to be made between an individual's fasting and the public's fasting. When an individual fasts there are no grounds for neshama yeterah - since he is fasting; when everybody has eaten their fill and drunk to their enjoyment, and they have neshama yeterah, it does then behoove one to recite the Blessing on Fragrances, and one must note that his blessing is being recited on the ways and mending of the world.