Why does Kooyong Gets Express Services?

Noticed this stopping pattern this morning on the Glen Waverley line—Kooyong gets express services, but Tooronga is skipped.

looking at patronage data (yes I researched on the train): 📊 AM Peak Entries: Tooronga (650) vs. Kooyong (250) 📊 PM Peak Entries: Tooronga (550) vs. Kooyong (350)

Tooronga has 81% more total passengers annually.

Not saying I’m biased just because I work near Tooronga… but, what’s the deal?