Well, Australia barely has any Starbucks. So that's irrelevant here. Standard size coffee cups here are the measure. The ratio of coffee to milk in milk drinks

Well, Australia barely has any Starbucks. So that's irrelevant here. Standard size coffee cups here are the measure. The ratio of coffee to milk in milk drinks is determined by the cup size as they are poured to the top. Keep Cups were sized to match what was normally used so it was a drop in replacement.