Storm Knight's DCs calculation

[d20Familiar]

Hi, minmaxboard!

I was tinkering with Stormwind's Storm Knight (basics spoilered below), and after several readings the explanation of those ECL1 DC17 gusts of wind still eludes me. Here's what I see:

• 1st level: 10 (base) + 2 (spell level) + 1 (Cha mod) + 1 (Mighty Dragonmark feat) = 14, instead of declared 17;
  
• 6th level: 10 (base) + 2 (spell level) + 1 (Cha mod) + 1 (Mighty Dragonmark feat) + 2 (Storm Sentry class level) = 16, instead of declared 19;
  

Gear (+2 CHA at ECL 6 is reasonable) still doesn't cover this 3-point gap, and at ECL1 one cannot afford even +2 stat-booster.

(click to show/hide)

Half-Elf
Warblade 3 / Half-Elf Fighter 1 / Storm Sentry 2 / XYZ 14
Feats (considering 2 flaws):

• 1st Least Dragonmark (Mark of Storm - gust of wind)
  
• 1st Mighty Dragonmark
• 1st Dragonmark Prodigy (updraft)
  
• 3rd Dragonmark Mastery / Quicken Dragonmark
• 6th Lesser Dragonmark

Curious thing: iconic Storm Sentry, "Fighter 2 / Swashbuckler 3 / SS 4" with Least and Lesser Dragonmark feats, has the same 12 CHA and DC17 which actually matches the formula 10 + 2 + 1 + 4 = 17.

So, am I missing something crucial or is it a case of simple miscalculation?

[kitep]

Your link is bad.  Just for other's sake, the correct link is http://community.wizards.com/content/forum-topic/3429956

I'm not seeing anything about Gust of Wind, DC 17 though.

[d20Familiar]

Yeah, my bad. Fixed the link.

[SorO_Lost]

I have no idea why it's marked DC 17 either, probably just a math error on the poster's part.

Minor tangent, DM-allowed adaptions of Desert Wind's Energy type pretty much solves all "elemental warrior" builds.