Was comparing the new option stats section in Thinkorswim with Livevol Pro and they differ by quite a bit. The IV in TOS is known to be incorrect and the HV is for a 20 day I think but for the Trade analysis for Calls and Puts, the volume and % bought on bid or ask are quite different from livevol - anyone know why?
TOS has quite a few issues. But still I think the IV is usually correct. Saying LiveVol is more correct is simply saying their interpolation methods are better. Which may or may not be true. But compared to IB, TOS does seem to differ so I trust my current broker.
Livevols model is more accurate for IV calcs. The models used at TOS are from 1989. All you need to do is check the IV between Puts and Calls and they should more or less be the same. With TOS they are a long way out as they don't account for the cost of carry.