It is difficult to compare two promotions based only on their click totals.
Books may have different genres, subgenres, covers, prices, reviews, retailer availability, series positions, promotional periods, and audiences.
The Fussy Librarian also personalizes recommendations, so two books may not be shown to exactly the same readers or receive identical exposure.
A lower click total does not necessarily mean something went wrong with the promotion. It may simply reflect differences in the books and the readers most likely to be interested in them.