The Ability to Add additional Skill Cost changes dynamically
Seen in - Eclipse
Skills can cost 2 per rank increase; 1 per rank increase; and 1/2 per rank increase depending on the skill. Need something to handle this.
Also, in eclipse, if you add 6 ranks to a "non-class skill", it automatically becomes a 'class skill' from that point forward.
Seen in 'D(liberation)20' skills can range in a five tier scale.