Getting off-topic, but MTR fares is based on a lot more than just distance. Very convoluted, as factors include geographical barriers, ex-KCR vs ex-MTR fares, time of completion of line, competition, and so on. Hard to decipher and plenty of unreasonable fares in the system.

It's be a lot simpler if it's simply based on distance.

And, while Octopus fare is generally cheaper than single-ticket, sometimes they're the same; and in some circumstances with the Light Rail in NW New Territories, Octopus fare costs more.