OK, here we go... To test our calculations lets create a scenario where there are 40bbs in the pot and villain bets 30bbs... How much equity do we need to make this call break even (EV must be equal to 0 in other words)?

Equity needed = 30 / (40 + 30 + 30) = 30%

So when we have 30% equity we must be breaking even. Lets calculate it your way;
EV = (100 * 0,30) - (30 * 0.70) = 30 - 21 = 9 <> 0

Lets calculate it my way;
EV = (100 * 0,30) - 30 = 30 - 30 = 0
or,
EV = (70 * 0,30) - (30 * 0,70) = 21 - 21 = 0

It's obvious that you made a mistake here. My calculations are right.