Sorry William, but you don't seem to have the hang of this.

Husson Lightning is from your original stable. It is yours automatically whenever it runs. As such, it's not worth ANY points. You simply have to choose any number of other horses (not in bold) which add up to no more than 100 points. The horses you chose originally (Volcada, Scenic Blast, Niconero & Jennings) added up to 110. All you had to do was replace one of them for a horse worth 10 points less.