p.105 Core Rule book
The skill table works on a similar principle, though Active Skill ratings costs are computed at new Rating x 2. If you are purchasing a brand new skill, find the desired rating on the table and pay that cumulative amount. For example, if you are purchasing the running skill for the first time, and are buying it up to Rating 3, you will pay 12 Karma.
It says cumulative for a Rank 3. To me that says Add up Rank 1 + Rank 2 + Rank 3 and cumulative reach the Sum of those values. Rank 1 is 2 Karma, Rank 2 is 6 Karma, Rank 3 is 12 Karma. To me that is cumulative 2+6+12 = 20 Karma.
I can't find somewhere in the errata that covers this.
Am I missing something?