Well, as somebody who stumbled into this thread it certainly was, um, interesting. Despite that I'd be interested in finding out more about the system. I will say that advancing through the lower levels in fewer fights than the middle/upper levels is not, from my point of view, good.
I do wonder how much certain factors can be taken into account. If a party tends to be timid and falls back to rest and recover they won't string together enough of those 20% encounters to get them to the point where the players are scared in combat. If you up the danger of the encounters they go up in level after very few play sessions. Who's the best tactician at the table can be a major factor. I'm driving at this: no system can take such factors into account but such factors are going to swamp very precise CR calculations.
I do wonder how much certain factors can be taken into account. If a party tends to be timid and falls back to rest and recover they won't string together enough of those 20% encounters to get them to the point where the players are scared in combat. If you up the danger of the encounters they go up in level after very few play sessions. Who's the best tactician at the table can be a major factor. I'm driving at this: no system can take such factors into account but such factors are going to swamp very precise CR calculations.