I don't think my post was probably that useful actually. I essentially ended up talking about terminology.

As for implied odds (since I didn't say a single thing), I tend not to like using formulae in-play (or much at all). If my equity to win is 4.38:1, the pot is $200 and it's costing me $50 to call... then i say: "I'm getting 4:1 on the pot, so I need to win at least 0.38*$50 on later streets."

The problem I have with using the Erpel formula above is that, when you multiply the $50 by 4.38, you are essentially adding $50 to $50 to $50 to $50, then you have to multiply 0.38 by $50 and then add it on. Then we subtract the pot. Whereas, only one step in this process is used if we first make an observation (our immediate odds on the pot and how far off they are what we need) that need not be stored in memory.

This is just me and the way i deal with numbers though so might not be that useful, but i'd have thought it a more natural way to work out amount needed to extract.