| I will admit my bad here. I suppose that despite our best efforts, something slips through the cracks. In playtest, no one ever brought up that problem, so I never put down explicitly what I was thinking. I originally had Chaos Blast as a 3rd level spell, but I increased the spell level because of its versatility.
The way I suggest you run it is that the -6 penalty should apply separately for each random attribute. Thus, if you want a Sculptor of Chaos to cast specifically a (for instance) Ray of Bunnies that instill Fear in those struck, it would be a base of DC 13 for a 4th level spell. Then you'd have a -18 penalty for controlling three separate traits, making the DC effectively 31.
In general, it's not particularly useful to control the make-up of the spell, unless you're trying to hit, say, a red dragon with a blast of cold. Your best bet is to just go for a -6 penalty and try to create a Cone. A medium-range Cone is incredibly huge, but you have to succeed a Spellcraft check that's equivalent to casting a 7th level spell, which isn't too overpowered. However, even at 9th level, you'd have a slight chance to be able to cast a cone of dispel magic, which would require an effective DC 25 to cast, but could prove incredibly useful. It's uses like that which make it necessary to have each random trait be separate for the sake of Shape Chaos.
It's a great versatility spell, one that nearly any Sculptor of Chaos should take. The Sculptor of Chaos was always my baby of a class, because it gives the player a huge range of options, if for nothing else than style's sake.
But back to the topic at hand, the official errata for Chaos Blast should state that, "Each of the three traits of Chaos Blast is considered separate for the sake of the Sculptor of Chaos ability Shape Chaos. Thus to control shape and effect would incur a -12 penalty to the Spellcraft check for Fluid Magic (-6 for each attribute)." | 
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