Apparently MSN and IB do not distinguish between the normal and mini options when Hoadley OSET or IV Calculator retrieve chains. Since IV is the same (normal vs mini) for the same strike and expiry, this has no effect on the volatility surface. However, now that the size of the chain(s) has doubled, retrieving from IB results in many blank prices, eg for SPY April and May monthly expiries, there are no Bid, Ask or Last prices shown. IB has always been clunky with Hoadley due to data retrieval limitations, this seems to be the straw that broke the camel's back. Anyone know a way around this?