The IV30 is coming from my data provider, and is using the old VIX style calculation.
For the new VIX, it's using SPX options and it uses a different approach (variance swap using the option prices directly instead of BS IV) so that the VIX is model independent.
Some references :
https://quant.stackexchange.com/questions/25157/how-was-the-old-vix-calculated
http://www.risklab.es/es/seminarios/pasados/mayo2004-1.pdf