DB,
Bolts is referring to fx options (I was comparing index options - not necessarily a valid comparison). I haven't looked at fx iv's for years but I do remember they are relatively low, single to low teen figures. Further, I think he may also be looking at options which are close to expiry or short-dated options, eg Eurex does one-week expiry options.
So if USD/JPY atm options have a 10% iv with a week to expiry, and assuming a constant volatility, then one just extrapolates the closing range (not an exact science). Years ago I remember Reuters FX reports attributed particularly heavy buying/selling in spot as banks defending specific levels where otc options would kick in (barrier, one-touch options?). This could be used as a supporting factor.
Thgen again, I may be totally wrong (that would be a surprise, wouldn't it?).
Grant.