I would imagine that the key difference is your actual cumulative volatility position. What do you think your net root time vega was in any of those spreads? My sense is that anyone who was long index vol this year, either outright or via any smart spreads did not fare well.
That's the point I'm making. Personally, if it wasn't for the backwardation in April and August, I would be down this year.
SIV66 - are you net long VX futures? The curve has been in steep contango and trading at historically high premium levels to spot for most of the year.
In order to be profitable, I would imagine your ratio of short to long contracts is net short, unless I'm oversimplifying here.
Trading the volatility of volatility has been interesting this year, however.
So yeah, vol is LOW.