Yes, that's correct. The odds calculator only calculates the odds all the way to showdown.
For the expected value of a call you can only know for sure that you'll see the next card, and not even that, if there are still other players to act that have position on you, since they might raise as well.
Then there are the implied odds, which IQA already mentioned in the other thread; that is that you may well extract (a lot) more money from the hand, if you hit your draw.
So calling a bet when you believe you need to improve your hand, in order to win it (i.e. you're on a draw), you should use the rule of 2 for the next card, unless you can see the river for free/cheap (i.e. all-in situations, or close to it, or against a player that does not know to value bet when ahead, giving away free cards).
The call is +EV when (using the rule of 2) the next card turns your hand into the winner often enough, to pay for the times you don't, or (using the rule of 4) if you don't have to pay to see the river card after that, taking into account pot odds and implied odds...
Joined: Jan '10
Age: 58 (M)
But don't forget pinotte..that's math just help us to make decision, don't forget other thing...figure your opponent hand...your feeling of your hand. As long as I know that math most effective on cash game, not good enough for micro/freeroll MTT cause so many liar player there and math not working.