Yeah, I checked the math and it works out - it's just that the Builder has a seriously ass-backwards way of handling things.
But yeah, everything looks to be in order - the two things I'd tweak would be getting a Fire Shard, and getting Explosive Pyre or Flame Spiral instead of Learned Boost. Everything else looks pretty decent.
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Twostuck, Homestuck RPG: http://www.gamefaqs.com/boards/8-gamefaqs-contests/62168402