SSH "Pot Equity Edge" understood correctly?

[Python]

SSH pgs. 36-37:
"If all four of your opponents call to see the turn, you will contribute 20 percent of the money, but your equity is 35 percent. This represents a "pot equity edge", as you will net a profit worth 15 percent of all the flop betting."

In reverse, if NOT all four opponents call, will I loose my pot equity edge?
I understood this as follows: If one opponent folds, I will contribute 25% of the money and my edge drops to 10%. If two folds, I loose my egde, because now I have to contribute 33%.

As a conclusion, the concept of pot equity edge should be handled with care in somewhat tight games.

What do you think?